exv10w9

Exhibit 10.9

INDEMNIFICATION AGREEMENT

This Indemnification Agreement (“Agreement”) is made as of ___, 2010 by and between CoreSite Realty Corporation, a Maryland corporation (the “Company”), and (“Indemnitee”).

RECITALS:

WHEREAS, directors, officers, and other persons in service to corporations or business enterprises are being increasingly subjected to expensive and time-consuming litigation relating to, among other things, matters that traditionally would have been brought only against the Company or business enterprise itself;

WHEREAS, highly competent persons have become more reluctant to serve as directors or in other capacities unless they are provided with adequate protection through insurance and adequate indemnification against inordinate risks of claims and actions against them arising out of their service to and activities on behalf of the corporation;

WHEREAS, the Board of Directors of the Company (the “Board”) has determined that the increased difficulty in attracting and retaining such persons is detrimental to the best interests of the Company and that the Company should act to assure such persons that there will be increased certainty of such protection in the future;

WHEREAS, (i) the charter of the Company (the “Charter”) authorize and the Bylaws of the Company (the “Bylaws”) require indemnification of the officers and directors of the Company, (ii) Indemnitee may also be entitled to indemnification pursuant to the Maryland General Corporation Law (“MGCL”) and (iii) the indemnification provisions set forth in the Charter, the Bylaws and the MGCL are not exclusive and contemplate that contracts may be entered into between the Company and members of the Board, officers and other persons with respect to indemnification;

WHEREAS, this Agreement is a supplement to and in furtherance of the Charter and Bylaws and any resolutions adopted pursuant thereto, and shall not be deemed a substitute therefore, nor to diminish or abrogate any rights of Indemnitee thereunder, and

WHEREAS, (i) Indemnitee does not regard the protection available under the Charter, Bylaws and insurance as adequate in the present circumstances, (ii) Indemnitee may not be willing to serve or continue to serve as a director without adequate protection, (iii) the Company desires Indemnitee to serve in such capacity, and (iv) Indemnitee is willing to serve, continue to serve and to take on additional service for or on behalf of the Company on the condition that he be so indemnified.

AGREEMENT:

NOW, THEREFORE, in consideration of the premises and the covenants contained herein, the Company and Indemnitee do hereby covenant and agree as follows:

Section 1. Definitions. (a) As used in this Agreement:

“Affiliate” of any specified Person shall mean any other Person controlling, controlled by or under common control with such specified Person.

“Change in Control” means a change in control of the Company occurring after the date hereof of a nature that would be required to be reported in response to Item 6(e) of Schedule 14A of Regulation 14A (or in response to any similar item on any similar schedule or form) promulgated under the Exchange Act, whether or not the Company is then subject to such reporting requirement; provided, however, that, without limitation, such a Change in Control shall be deemed to have occurred if, after the date hereof (i) any “person” (as such term is used in Sections 13(d) and 14(d) of the Exchange Act) is or becomes the “beneficial owner” (as defined in Rule 13d-3 under the Exchange Act), directly or indirectly, of securities of the Company representing 15% or more of the combined voting power of all of the Company’s then-outstanding securities entitled to vote generally in the election of directors without the prior approval of at least two-thirds of the members of the Board in office immediately prior to such person’s attaining such percentage interest; (ii) the Company is a party to a merger, consolidation, sale of assets, plan of liquidation or other reorganization not approved by at least two-thirds of the members of the Board then in office, as a consequence of which members of the Board in office immediately prior to such transaction or event constitute less than a majority of the Board thereafter; or (iii) at any time, a majority of the members of the Board are not individuals (A) who were directors as of the date hereof or (B) whose election by the Board or nomination for election by the Company’s stockholders was approved by the affirmative vote of at least two-thirds of the directors then in office who were directors as of the date hereof or whose election for nomination for election was previously so approved.

“Corporate Status” describes the status of a person who is or was a director, officer, employee or agent of (i) the Company or (ii) any other corporation, limited liability company, partnership or joint venture, trust, employee benefit plan or other enterprise which such person is or was serving at the request of the Company. As a clarification and without limiting the circumstances in which Indemnitee may be serving at the request of the Company, service by Indemnitee shall be deemed to be at the request of the Company if Indemnitee serves or served as a director, trustee, officer, partner, manager, managing member, fiduciary, employee or agent of any corporation, partnership, limited liability company, joint venture, trust, employee benefit plan or other enterprise (i) of which a majority of the voting power or equity interest is owned directly or indirectly by the Company or (ii) the management of which is controlled directly or indirectly by the Company.

“Disinterested Director” means a director of the Company who is not and was not a party to the Proceeding in respect of which indemnification and/or advance of Expenses is is sought by Indemnitee.

“Enterprise” shall mean the Company and any other corporation, limited liability company, partnership, joint venture, trust, employee benefit plan or other enterprise of which Indemnitee is or was serving at the request of the Company as a director, officer, employee, agent or fiduciary.

“Expenses” shall mean all reasonable costs, expenses, fees and charges (including without limitation) attorneys’ fees, retainers, court costs, transcript costs, fees of experts, witness fees, travel expenses, duplicating costs, printing and binding costs, telephone

-2-

charges, postage, delivery service fees, and all other disbursements or expenses of the types customarily incurred in connection with prosecuting, defending, preparing to prosecute or defend, investigating, being or preparing to be a witness in, or otherwise participating in, a Proceeding. Expenses also shall include, without limitation, (i) expenses incurred in connection with any appeal resulting from, incurred by Indemnitee in connection with, arising out of respect of or relating to, any Proceeding, including without limitation, the premium, security for, and other costs relating to any cost bond, supersedes bond, or other appeal bond or its equivalent, (ii) for purposes of Section 12(e) only, expenses incurred by Indemnitee in connection with the interpretation, enforcement or defense of Indemnitee’s rights under this Agreement, by litigation or otherwise, (iii) any federal, state, local or foreign taxes imposed on Indemnitee as a result of the actual or deemed receipt of any payments under this Agreement, and (iv) any interest, assessments or other charges in respect of the foregoing.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.

“Indemnity Obligations” shall mean all obligations of the Company to Indemnitee under this Agreement, including the Company’s obligations to provide indemnification to Indemnitee and advance Expenses to Indemnitee under this Agreement.

“Independent Counsel” shall mean a law firm, or a member of a law firm, that is experienced in matters of corporation law and neither presently is, nor in the past five years has been, retained to represent: (i) the Company or Indemnitee in any matter material to either such party (other than with respect to matters concerning the Indemnitee under this Agreement, or of other indemnitees under similar indemnification agreements), or (ii) any other party to the Proceeding giving rise to a claim for indemnification hereunder; provided, however, that the term “Independent Counsel” shall not include any person who, under the applicable standards of professional conduct then prevailing, would have a conflict of interest in representing either the Company or Indemnitee in an action to determine Indemnitee’s rights under this Agreement.

“Liabilities” means all claims, liabilities, damages, losses, judgments, orders, fines, penalties and other amounts payable that are actually incurred by Indemnitee in connection with, arising out of, or in respect of or relating to any Proceeding, including, without limitation, amounts paid in settlement in any Proceeding and all costs and expenses in complying with any judgment, order or decree issued or entered in connection with any Proceeding or any settlement agreement, stipulation or consent decree entered into or issued in settlement of any Proceeding. For the purpose hereof, references to “fines” shall include any excise tax assessed with respect to any employee benefit plan.

“Person” shall mean any individual, corporation, partnership, limited partnership, limited liability company, trust, governmental agency or body or any other legal entity.

“Proceeding” shall mean any threatened, pending or completed action, claim, suit, arbitration, alternate dispute resolution mechanism, formal or informal hearing, inquiry or investigation, litigation, inquiry, administrative hearing or any other actual, threatened or completed judicial, administrative or arbitration proceeding (including, without limitation, any such proceeding under the Securities Act of 1933, as amended, or the Exchange Act or any other federal law, state law, statute or regulation), whether brought in the right of the Company or otherwise, and whether of a civil, criminal, administrative

-3-

or investigative nature, in each case, in which Indemnitee was, is or will be, or is threatened to be, involved as a party, witness or otherwise by reason of the Indemnitee’s Corporate Status, by reason of any actual or alleged action taken or omission by Indemnitee or of any action or omission on Indemnitee’s part while acting in Indemnittee’s Corporate Status, in each case whether or not Indemnitee still has such Corporate Status at the time any liability or expense is incurred for which indemnification, reimbursement, or advancement of Expenses can be provided under this Agreement.

“Sponsor Entities” means (i) The Carlyle Group and (ii) any be Affiliate of The Carlyle Group, provided, however, that neither the Company nor any of its subsidiaries shall be considered Sponsor Entities hereunder.

Section 2. General. The Company shall indemnify, and advance Expenses to, Indemnitee (a) as provided in this Agreement and (b) otherwise to the maximum extent permitted by Maryland law in effect on the date hereof and as amended from time to time; provided, however, that no change in Maryland law shall have the effect of reducing the benefits available to Indemnitee hereunder based on Maryland law as in effect on the date hereof. The rights of Indemnitee provided in this Section 2 shall include, without limitation, the rights set forth in the other sections of this Agreement, including any additional indemnification permitted by Section 2-418(g) of the MGCL.

Section 3. Standard for Indemnification. If, by reason of Indemnitee’s Corporate Status, Indemnitee is, or is threatened to be, made a party to any Proceeding, Indemnitee shall be indemnified against all Expenses and Liabilities incurred by him or on his behalf in connection with any such Proceeding unless it is established that (a) the act or omission of Indemnitee was material to the matter giving rise to the Proceeding and (i) was committed in bad faith or (ii) was the result of active and deliberate dishonesty, (b) Indemnitee actually received an improper personal benefit in money, property or services or (c) in the case of any criminal Proceeding, Indemnitee had reasonable cause to believe that his conduct was unlawful.

Section 4. Certain Limits on Indemnification. Notwithstanding any other provision of this Agreement (other than Section 5), Indemnitee shall not be entitled to:

(a) indemnification hereunder if the Proceeding was one by or in the right of the Company and Indemnitee is adjudged to be liable to the Company;

(b) indemnification hereunder if Indemnitee is adjudged to be liable on the basis that personal benefit was improperly received in any Proceeding charging improper personal benefit to Indemnitee, whether or not involving action in the Indemnitee’s Corporate Status; or

(c) indemnification or advance of Expenses hereunder if the Proceeding was brought by Indemnitee unless: (i) the Proceeding was brought to enforce indemnification under this Agreement, but then only to the extent in accordance with and as authorized by Section 7 and Section 12 of this Agreement, or (ii) the Charter or Bylaws, a resolution of the stockholders entitled to vote generally in the election of directors or of the Board or an agreement approved by the Board to which the Company is a party expressly provide otherwise.

-4-

Section 5. Court-Ordered Indemnification. Notwithstanding any other provision of this Agreement, a court of appropriate jurisdiction, upon application of Indemnitee and such notice as the court shall require, may order indemnification in the following circumstances:

(a) if it determines Indemnitee is entitled to reimbursement under Section 2-418(d)(1) of the MGCL, the court shall order indemnification, in which case Indemnitee shall be entitled to recover the Expenses of securing such reimbursement; or

(b) if it determines that Indemnitee is fairly and reasonably entitled to indemnification in view of all the relevant circumstances, whether or not Indemnitee (i) has met the standards of conduct set forth in Section 2-418(b) of the MGCL or (ii) has been adjudged liable for receipt of an improper personal benefit under Section 2-418(c) of the MGCL, the court may order such indemnification as the court shall deem proper. However, indemnification with respect to any Proceeding by or in the right of the Company or in which liability shall have been adjudged in the circumstances described in Section 2-418(c) of the MGCL shall be limited to Expenses.

Section 6. Indemnification for Expenses of a Party Who is Wholly or Partly Successful. Notwithstanding any other provision of this Agreement, and without limiting any such provision, to the extent that Indemnitee was or is, by reason of his Corporate Status, made a party to (or otherwise becomes a participant in) any Proceeding and is successful, on the merits or otherwise, in the defense of such Proceeding, Indemnitee shall be indemnified for all Expenses and Liabilities incurred by him or on his behalf in connection therewith. If Indemnitee is not wholly successful in such Proceeding but is successful, on the merits or otherwise, as to one or more but less than all claims, issues or matters in such Proceeding, the Company shall indemnify Indemnitee under this Section 6 for all Liabilities and Expenses incurred by him or on his behalf in connection with each such claim, issue or matter, allocated on a reasonable and proportionate basis. For purposes of this Section 6 and, without limitation, the termination of any claim, issue or matter in such a Proceeding by dismissal, with or without prejudice, shall be deemed to be a successful result as to such claim, issue or matter.

Section 7. Advances of Expenses. Notwithstanding any provision of this Agreement to the contrary, the Company shall advance, the Expenses incurred by Indemnitee in connection with any Proceeding, and such advancement shall be made within ten (10) days after the receipt by the Company of a statement or statements requesting such advances from time to time, whether prior to or after final disposition of any Proceeding. Advances shall be unsecured and interest free. Advances shall be made without requiring a preliminary determination of Indemnitee’s ultimate entitlement to indemnification under the other provisions of this Agreement. Advances shall include any and all Expenses incurred pursuing an action to enforce this right of advancement, including Expenses incurred preparing and forwarding statements to the Company to support the advances claimed. Such statement or statements shall reasonably evidence the Expenses incurred by Indemnitee and shall include or be preceded or accompanied by a written affirmation by Indemnitee of Indemnitee’s good faith belief that the standard of conduct necessary for indemnification by the Company as authorized by law and by this Agreement has been met and a written undertaking by or on behalf of Indemnitee to reimburse the portion of any Expenses advanced to Indemnitee relating to claims, issues or matters in the Proceeding as to which it shall ultimately be established that the standard of conduct for indemnification has not been met by Indemnitee and which have not been successfully resolved as described in Section 6 of this Agreement. The affirmation and undertaking shall be in substantially the form attached hereto as Exhibit A or in such form as may be required under applicable law as in effect at the time of the execution thereof. To the extent that Expenses

-5-

advanced to Indemnitee do not relate to a specific claim, issue or matter in the Proceeding, such Expenses shall be allocated on a reasonable and proportionate basis. The undertaking required by this Section 7 shall be an unlimited general obligation by or on behalf of Indemnitee and shall be accepted without reference to Indemnitee’s financial ability to repay such advanced Expenses and without any requirement to post security therefor.

Section 8. Indemnification For Expenses of a Witness. Notwithstanding any other provision of this Agreement, to the fullest extent permitted by applicable law and to the extent that Indemnitee is, by reason of Indemnitee’s Corporate Status, a witness in any Proceeding to which Indemnitee is not a party, he shall be indemnified against all Expenses and Liabilities suffered or incurred by him or on his behalf in connection therewith.

Section 9. Procedure for Notification and Defense of Claim.

(a) Indemnitee shall notify the Company in writing of any Proceeding with respect to which Indemnitee intends to seek indemnification or advancement of Expenses hereunder as soon as reasonably practicable following the receipt by Indemnitee of written notice thereof. The written notification to the Company shall include a description of the nature of the Proceeding and the facts underlying the Proceeding. To obtain indemnification under this Agreement, Indemnitee shall submit to the Company a written request, including therein or therewith such documentation and information as is reasonably available to Indemnitee and is reasonably necessary to determine whether and to what extent Indemnitee is entitled to indemnification following the final disposition of such action, suit or proceeding. Any delay or failure by Indemnitee to notify the Company hereunder will not relieve the Company from any liability which it may have to Indemnitee hereunder or otherwise under this Agreement, and any delay or failure in so notifying the Company shall not constitute a waiver by Indemnitee of any rights under this Agreement unless the Company’s ability to defend in such Proceeding or to obtain proceeds under any insurance policy is materially and adversely prejudiced thereby, and then only to the extent the Company is thereby actually so prejudiced. The Secretary of the Company shall, promptly upon receipt of such a request for indemnification, advise the Board in writing that Indemnitee has requested indemnification.

(b) In the event Indemnitee is entitled to indemnification and/or advancement of Expenses with respect to any Proceeding, Indemnitee may, at Indemnitee’s option, (i) retain counsel selected by Indemnitee and approved by the Company (which approval shall not to be unreasonably withheld, conditioned or delayed) to defend Indemnitee in such Proceeding, at the sole expense of the Company, or (ii) have the Company assume the defense of Indemnitee in such Proceeding, in which case the Company shall assume the defense of such Proceeding with counsel selected by the Company and approved by Indemnitee (which approval shall not be unreasonably withheld, conditioned or delayed) within ten (10) days of the Company’s receipt of written notice of Indemnitee’s election to cause the Company to do so. If the Company is required to assume the defense of any such Proceeding, it shall engage legal counsel for such defense, and the Company shall be solely responsible for all fees and expenses of such legal counsel and otherwise of such defense. Such legal counsel may represent both Indemnitee and the Company (and/or any other party or parties entitled to be indemnified by the Company with respect to such matter) unless, in the reasonable opinion of legal counsel to Indemnitee, there is a conflict of interest between Indemnitee and the Company (or any other such party or parties) or there are legal defenses available to Indemnitee that are not available to the Company (or any such other party or parties). Notwithstanding either party’s assumption of responsibility for defense of a Proceeding, each party shall have the right to engage separate counsel at its own expense. The party having responsibility for defense of a Proceeding shall

-6-

provide the other party and its counsel with all copies of pleadings and material correspondence relating to the proceeding. Indemnitee and the Company shall reasonably cooperate in the defense of any Proceeding with respect to which indemnification is sought hereunder, regardless of whether the Company or Indemnitee assumes the defense thereof. Indemnitee may not settle or compromise any Proceeding without the prior written consent of the Company, which consent shall not be unreasonably withheld, conditioned or delayed. The Company may not settle or compromise any proceeding without the prior written consent of Indemnitee, which consent shall not be unreasonably withheld, conditioned or delayed.

Section 10. Procedure Upon Application for Indemnification.

(a) Upon written request by Indemnitee for indemnification pursuant to Section 9(a) above, a determination, if required by applicable law, with respect to Indemnitee’s entitlement thereto shall promptly be made in the specific case: (i) if a Change in Control shall have occurred, by Independent Counsel, in a written opinion to the Board, a copy of which shall be delivered to Indemnitee, which Independent Counsel shall be selected by the Indemnitee and approved by the Board in accordance with Section 2-418(e)(2)(ii) of the MGCL, which approval will not be unreasonably withheld; or (ii) if a Change in Control shall not have occurred, (A) by the Board by a majority vote of a quorum consisting of Disinterested Directors or, if such a quorum cannot be obtained, then by a majority vote of a duly authorized committee of the Board consisting solely of one or more Disinterested Directors, (B) if Independent Counsel has been selected by the Board in accordance with Section 2-418(e)(2)(ii) of the MGCL and approved by the Indemnitee, which approval shall not be unreasonably withheld, by Independent Counsel, in a written opinion to the Board, a copy of which shall be delivered to Indemnitee or (C) if so directed by a majority of the members of the Board, by the stockholders of the Company. If it is so determined that Indemnitee is entitled to indemnification, payment to Indemnitee shall be made within ten days after such determination. Indemnitee shall cooperate with the person, persons or entity making such determination with respect to Indemnitee’s entitlement to indemnification, including providing to such person, persons or entity upon reasonable advance request any documentation or information which is not privileged or otherwise protected from disclosure and which is reasonably available to Indemnitee and reasonably necessary to such determination in the discretion of the Board or Independent Counsel if retained pursuant to clause (ii)(B) of this Section 10(a). Any Expenses incurred by Indemnitee in so cooperating with the person, persons or entity making such determination shall be borne by the Company (irrespective of the determination as to Indemnitee’s entitlement to indemnification) and the Company shall indemnify and hold Indemnitee harmless therefrom.

(b) The Company shall pay the reasonable fees and expenses of Independent Counsel, if one is appointed.

(c) In the event the determination of entitlement to indemnification is to be made by Independent Counsel pursuant to Section 9(a) hereof, (i) the Independent Counsel shall be selected by the Company within ten (10) days of the Submission Date (the cost of each such counsel to be paid by the Company), (ii) shall give written notice to Indemnitee advising it of the identity of the Independent Counsel so selected and (iii) Indemnitee may, within ten (10) days after such written notice of selection shall have been given, deliver to the Company Indemnitee’s written objection to such selection. Absent a timely objection, the person so selected shall act as Independent Counsel. If a written objection is so made by Indemnitee, the Independent Counsel so selected may not serve as Independent Counsel unless and until such objection is withdrawn. If no Independent Counsel shall have been selected and not objected to before the later of (i) thirty (30) days after the later of submission by Indemnitee of a written request for

-7-

indemnification pursuant to Section 9(a) hereof (the “Submission Date”) and (ii) ten (10) days after the final disposition of the Proceeding, each of the Company and Indemnitee shall select a law firm or member of a law firm meeting the qualifications to serve as Independent Counsel, and such law firms or members of law firms shall select the Independent Counsel. Upon the due commencement of any judicial proceeding or arbitration pursuant to Section 12(a) of this Agreement, Independent Counsel shall be discharged and relieved of any further responsibility in such capacity (subject to the applicable standards of professional conduct then prevailing).

Section 11. Presumptions and Effect of Certain Proceedings.

(a) In making a determination with respect to entitlement to indemnification hereunder, the person or persons or entity making such determination shall, to the fullest extent not prohibited by law, presume that Indemnitee is entitled to indemnification under this Agreement if Indemnitee has submitted a request for indemnification in accordance with Section 10(a) of this Agreement, and the Company shall, to the fullest extent not prohibited by law, have the burden of proof to overcome that presumption in connection with the making by any person, persons or entity of any determination contrary to that presumption. Neither the failure of the Company (including by its directors or independent legal counsel) to have made a determination prior to the commencement of any action pursuant to this Agreement that indemnification is proper in the circumstances because Indemnitee has met the applicable standard of conduct, nor an actual determination by the Company (including by its directors or independent legal counsel) that Indemnitee has not met such applicable standard of conduct, shall be a defense to the action or create a presumption that Indemnitee has not met the applicable standard of conduct.

(b) Subject to Section 12(e), if the person, persons or entity empowered or selected under Section 9 of this Agreement to determine whether Indemnitee is entitled to indemnification shall not have made a determination within sixty (60) days after receipt by the Company of the request therefore, the requisite determination of entitlement to indemnification shall, to the fullest extent not prohibited by law, be deemed to have been made and Indemnitee shall be entitled to such indemnification, absent a prohibition of such indemnification under applicable law; provided, however, that such 60-day period may be extended for a reasonable time, not to exceed an additional sixty (60) days, if (i) the determination is to be made by Independent Counsel and Indemnitee objects to the Company’s selection of Independent Counsel and (ii) the Independent Counsel ultimately selected requires such additional time for the obtaining or evaluating of documentation and/or information relating thereto.

(c) The termination of any Proceeding or of any claim, issue or matter therein, by judgment, order, settlement or conviction, or upon a plea of nolo contendere or its equivalent, shall not (except as otherwise expressly provided in this Agreement) adversely affect the right of Indemnitee to indemnification or create a presumption that Indemnitee did not act in good faith and in a manner which he reasonably believed to be in or not opposed to the best interests of the Company or, with respect to any criminal Proceeding, that Indemnitee had reasonable cause to believe that Indemnitee’s conduct was unlawful.

(d) The knowledge and/or actions, or failure to act, of any director, officer, agent or employee of the Enterprise shall not be imputed to Indemnitee for purposes of determining the right to indemnification under this Agreement.

Section 12. Remedies of Indemnitee.

-8-

(a) Subject to Section 12(e), in the event that (i) a determination is made pursuant to Section 10(a) of this Agreement that Indemnitee is not entitled to indemnification under this Agreement, (ii) advancement of Expenses is not timely made pursuant to Section 7 of this Agreement, (iii) no determination of entitlement to indemnification shall have been made pursuant to Section 10(a) of this Agreement within ninety (90) days after receipt by the Company of the request for indemnification, (iv) payment of indemnification is not made pursuant to Section 6 of this Agreement within ten (10) days after receipt by the Company of a written request therefore, (v) payment of indemnification pursuant to any other section of this Agreement, the Charter or the Bylaws is not made within ten (10) days after a determination has been made that Indemnitee is entitled to indemnification, or (vi) in the event that the Company or any other person takes or threatens to take any action to declare this Agreement void or unenforceable, or institutes any litigation or other action or Proceeding designed to deny, or to recover from, the Indemnitee the benefits provided or intended to be provided to the Indemnitee hereunder, Indemnitee shall be entitled to an adjudication by a court of Indemnitee’s entitlement to such indemnification and/or advancement of Expenses. Alternatively, Indemnitee, at Indemnitee’s option, may seek an award in arbitration to be conducted by a single arbitrator pursuant to the Commercial Arbitration Rules of the American Arbitration Association. The Company shall not oppose Indemnitee’s right to seek any such adjudication or award in arbitration.

(b) In the event that a determination shall have been made pursuant to Section 10(a) of this Agreement that Indemnitee is not entitled to indemnification, any judicial proceeding or arbitration commenced pursuant to this Section 12 shall be conducted in all respects as a de novo trial, or arbitration, on the merits and Indemnitee shall not be prejudiced by reason of that adverse determination. In any judicial proceeding or arbitration commenced pursuant to this Section 12, the Company shall have the burden of proving Indemnitee is not entitled to indemnification or advancement of Expenses, as the case may be.

(c) If a determination shall have been made pursuant to Section 10(a) of this Agreement that Indemnitee is entitled to indemnification, the Company shall be bound by such determination in any judicial proceeding or arbitration commenced pursuant to this Section 12, absent a prohibition of such indemnification under applicable law.

(d) The Company shall, to the fullest extent not prohibited by law, be precluded from asserting in any judicial proceeding or arbitration commenced pursuant to this Section 12 that the procedures and presumptions of this Agreement are not valid, binding and enforceable and shall stipulate in any such court or before any such arbitrator that the Company is bound by all the provisions of this Agreement.

(e) In the event that Indemnitee, pursuant to this Section 12, seeks a judicial adjudication of or an award in arbitration to enforce his rights under, or to recover damages for breach of, this Agreement, if Indemnitee is successful, Indemnitee shall be entitled to recover from the Company, and shall be indemnified by the Company for, any and all Expenses actually and reasonably incurred by him in such judicial adjudication or arbitration. If it shall be determined in such judicial adjudication or arbitration that Indemnitee is entitled to receive part but not all of the indemnification or advance of Expenses sought, the Expenses incurred by Indemnitee in connection with such judicial adjudication or arbitration shall be appropriately prorated.

(f) Interest shall be paid by the Company to Indemnitee at the maximum rate allowed to be charged for judgments under the Courts and Judicial Proceedings Article of the

-9-

Annotated Code of Maryland for amounts which the Company pays or is obligated to pay for the period commencing with the date on which the Company was requested to advance expenses in accordance with Section 7 of this Agreement or to make the determination of entitlement to indemnification under Section 12(a) above and ending on the date such payment is made to Indemnitee by the Company

Section 13. Non-exclusivity; Survival of Rights; Insurance; Privacy of Indemnification; Subrogation.

(a) The rights of indemnification and to receive advancement of Expenses as provided by this Agreement shall not be deemed exclusive of any other rights to which Indemnitee may at any time be entitled under applicable law, the Charter, the Bylaws, any agreement, a vote of stockholders or a resolution of directors, or otherwise. No amendment, alteration or repeal of this Agreement or of any provision hereof shall limit or restrict any right of Indemnitee under this Agreement in respect of any action taken or omitted by such Indemnitee in Indemnitee’s Corporate Status prior to such amendment, alteration or repeal. To the extent that a change in Maryland law, whether by statute or judicial decision, permits greater indemnification or advancement of Expenses than would be afforded currently under the Charter, the Bylaws and/or this Agreement, it is the intent of the parties hereto that Indemnitee shall enjoy by this Agreement the greater benefits so afforded by such change. No right or remedy herein conferred is intended to be exclusive of any other right or remedy, and every other right and remedy shall be cumulative and in addition to every other right and remedy given hereunder or now or hereafter existing at law or in equity or otherwise. The assertion or employment of any right or remedy hereunder, or otherwise, shall not prevent the concurrent assertion or employment of any other right or remedy.

(b) The Company hereby acknowledges that Indemnitee has certain rights to indemnification, advancement of Expenses and/or insurance provided by the Sponsor Entities. The Company hereby agrees (i) that it is the Indemnitor of first resort for any claims made against Indemnitee by reason of his Corporate Status (i.e., its obligations to Indemnitee are primary and any obligation of the Sponsor Entities to advance Expenses or to provide indemnification for the same Expenses or Liabilities incurred by Indemnitee by reason of his Corporate Status are secondary), (ii) that it shall be required to advance the full amount of Expense incurred by Indemnitee by reason of his Corporate Status and shall be liable for the full amount of all Expenses and Liabilities to the extent legally permitted and as required by the terms of this Agreement and the Company’s Charter or Bylaws (or any other agreement between the Company and Indemnitee), without regard to any rights Indemnitee may have against the Sponsor Entities, and, (iii) that it irrevocably waives, relinquishes and releases the Sponsor Entities from any and all claims against the Sponsor Entities for contribution or subrogation in respect of any claims made against Indemnitee by reason of his Corporate Status. The Company further agrees that no advancement or payment by the Sponsor Parties on behalf of Indemnitee with respect to any claim for which Indemnitee has sought indemnification from the Company pursuant to this Agreement shall affect the foregoing and the Sponsor Entities shall have a right of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of Indemnitee against the Company as permitted by this Agreement. The Company and Indemnitee agree that the Sponsor Entities are express third party beneficiaries of the terms of this Section 16(b).

(c) [Except as provided in paragraph (b) above, t][T]he Company shall not be liable under this Agreement to make any payment of amounts otherwise indemnifiable or

-10-

payable or reimbursable as Expenses hereunder if and to the extent that Indemnitee has otherwise actually received such payment under any insurance policy, contract, agreement or otherwise. [Include language in bold for directors nominated by Sponsor Entities]

(d) To the extent that the Company maintains an insurance policy or policies providing liability insurance for directors, officers, employees, or agents of the Company or of any other corporation, partnership, joint venture, trust, employee benefit plan or other enterprise which such person serves at the request of the Company, Indemnitee shall be covered by such policy or policies in accordance with its or their terms to the maximum extent of the coverage available for any such director, officer, employee or agent under such policy or policies. If, at the time of the receipt of a notice of a claim pursuant to the terms hereof, the Company has director and officer liability insurance in effect, the Company shall give prompt notice of the commencement of such proceeding to the insurers in accordance with the procedures set forth in the respective policies. The Company shall thereafter take all necessary or desirable action to cause such insurers to pay, on behalf of the Indemnitee, all amounts payable as a result of such proceeding in accordance with the terms of such policies.

(e) The indemnification provided for in this Agreement will remain in full force and effect regardless of any investigation made by or on behalf of Indemnitee.

Section 14. Duration of Agreement; Not Employment Contract. This Agreement shall continue until and terminate on the date that Indemnitee is no longer subject to any actual or possible Proceeding (including any rights of appeal thereto and any Proceeding commenced by Indemnitee pursuant to Section 12 of this Agreement). This Agreement shall be binding upon the Company and its successors and assigns and shall inure to the benefit of Indemnitee and Indemnitee’s heirs, executors and administrators. This Agreement shall not be deemed an employment contract between the Company (or any of its subsidiaries or any Enterprise) and Indemnitee. Indemnitee specifically acknowledges that Indemnitee’s employment with the Company (or any of its subsidiaries or any Enterprise), if any, is at will, and the Indemnitee may be discharged at any time for any reason, with or without cause, except as may be otherwise provided in any written employment contract between Indemnitee and the Company (or any of its subsidiaries or any Enterprise), other applicable formal severance policies duly adopted by the Board, or, with respect to service as a director of the Company, by the Charter, the Bylaws and the MGCL.

Section 15. Severability. If any provision or provisions of this Agreement shall be held to be invalid, illegal or unenforceable for any reason whatsoever: (a) the validity, legality and enforceability of the remaining provisions of this Agreement (including without limitation, each portion of any Section of this Agreement containing any such provision held to be invalid, illegal or unenforceable, that is not itself invalid, illegal or unenforceable) shall not in any way be affected or impaired thereby and shall remain enforceable to the fullest extent permitted by law; (b) such provision or provisions shall be deemed reformed to the extent necessary to conform to applicable law and to give the maximum effect to the intent of the parties hereto; and (c) to the fullest extent possible, the provisions of this Agreement (including, without limitation, each portion of any Section of this Agreement containing any such provision held to be invalid, illegal or unenforceable, that is not itself invalid, illegal or unenforceable) shall be construed so as to give effect to the intent manifested thereby.

Section 16. Enforcement.

-11-

(a) The Company expressly confirms and agrees that it has entered into this Agreement and assumed the obligations imposed on it hereby in order to induce Indemnitee to serve as a director or officer of the Company, and the Company acknowledges that Indemnitee is relying upon this Agreement in serving as a director or officer of the Company.

(b) This Agreement constitutes the entire agreement between the parties hereto with respect to the subject matter hereof and supersedes all prior agreements and understandings, oral, written and implied, between the parties hereto with respect to the subject matter hereof; provided, however, that this Agreement is a supplement to and in furtherance of the Charter, the Bylaws and applicable law, and shall not be deemed a substitute therefore, nor to diminish or abrogate any rights of Indemnitee thereunder.

Section 17. Modification and Waiver. No supplement, modification or amendment of this Agreement shall be binding unless executed in writing by the parties thereto. No waiver of any of the provisions of this Agreement shall be deemed or shall constitute a waiver of any other provisions of this Agreement nor shall any waiver constitute a continuing waiver.

Section 18. Notices. All notices, requests, demands and other communications under this Agreement shall be in writing and shall be deemed to have been duly given if (a) delivered by hand and receipted for by the party to whom said notice or other communication shall have been directed, (b) mailed by certified or registered mail with postage prepaid, on the third business day after the date on which it is so mailed, (c) mailed by reputable overnight courier and receipted for by the party to whom said notice or other communication shall have been directed or (d) sent by facsimile transmission, with receipt of oral confirmation that such transmission has been received:

(a) If to Indemnitee, at the address indicated on the signature page of this Agreement, or such other address as Indemnitee shall provide to the Company.

(b) If to the Company to

CoreSite Realty Corporation
1050 17^th Street, Suite 800
Denver, CO 80265
Tel: [•]
Attn: [•]

or to any other address as may have been furnished to Indemnitee by the Company.

Section 19. Applicable Law and Consent to Jurisdiction. This Agreement and the legal relations among the parties shall be governed by, and construed and enforced in accordance with, the laws of the State of Maryland, without regard to its conflict of laws rules. The Company and Indemnitee hereby irrevocably and unconditionally (i) agree that any action or proceeding arising out of or in connection with this Agreement shall be brought only in the United States District Court For the District of Maryland, Northern Division (the “Maryland Court”), and not in any other state or federal court in the United States of America or any court in any other country, (ii) consent to submit to the exclusive jurisdiction of the Maryland Court for purposes of any action or proceeding arising out of or in connection with this Agreement, (iii) waive any objection to the laying of venue of any such action or proceeding in the Maryland Court, and (iv) waive, and agree not to plead or to make, any claim that any such action or proceeding brought in the Maryland Court has been brought in an improper or inconvenient forum.

-12-

Section 20. Counterparts. This Agreement may be executed in one or more counterparts, each of which shall for all purposes be deemed to be an original but all of which together shall constitute one and the same Agreement. Only one such counterpart signed by the party against whom enforceability is sought needs to be produced to evidence the existence of this Agreement.

Section 21. Third-Party Beneficiaries. The Sponsor Entities are intended third-party beneficiaries of this Agreement.

Section 22. Miscellaneous. Use of the masculine pronoun shall be deemed to include usage of the feminine pronoun where appropriate. The headings of the paragraphs of this Agreement are inserted for convenience only and shall not be deemed to constitute part of this Agreement or to affect the construction thereof.

-13-

EXHIBIT A

FORM OF AFFIRMATION AND UNDERTAKING TO REPAY EXPENSES ADVANCED

The Board of Directors of CoreSite Realty Corporation

Re: Undertaking to Repay Expenses Advanced

Ladies and Gentlemen:

This undertaking is being provided pursuant to that certain Indemnification Agreement dated the day of , 2010, by and between CoreSite Realty Corporation, a Maryland corporation (the “Company”), and the undersigned Indemnitee (the “Indemnification Agreement”), pursuant to which I am entitled to advance of Expenses in connection with [Description of Proceeding] (the “Proceeding”).

Terms used herein and not otherwise defined shall have the meanings specified in the Indemnification Agreement.

I am subject to the Proceeding by reason of my Corporate Status or by reason of alleged actions or omissions by me in such capacity. I hereby affirm my good faith belief that at all times, insofar as I was involved as [a director] [an officer] of the Company, in any of the facts or events giving rise to the Proceeding, I (1) did not act with bad faith or active or deliberate dishonesty, (2) did not receive any improper personal benefit in money, property or services and (3) in the case of any criminal proceeding, had no reasonable cause to believe that any act or omission by me was unlawful.

In consideration of the advance of Expenses by the Company for reasonable attorneys’ fees and related Expenses incurred by me in connection with the Proceeding (the “Advanced Expenses”), I hereby agree that if, in connection with the Proceeding, it is established that (1) an act or omission by me was material to the matter giving rise to the Proceeding and (a) was committed in bad faith or (b) was the result of active and deliberate dishonesty or (2) I actually received an improper personal benefit in money, property or services or (3) in the case of any criminal proceeding, I had reasonable cause to believe that the act or omission was unlawful, then I shall promptly reimburse the portion of the Advanced Expenses relating to the claims, issues or matters in the Proceeding as to which the foregoing findings have been established.

IN WITNESS WHEREOF, I have executed this Affirmation and Undertaking on this day of , 2010.

-15-


CORESITE REALTY CORPORATION						INDEMNITEE

By:

Name:						Name:

Office:						Address: