-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 VS/uewa10/smOa8Vl4LJvRTc6/nOJmngbpUjNYJDjRIpqzV7yP3IRUoq9NaLoyGh
 WipOdrceUzvybycEg7sOwg==

<SEC-DOCUMENT>0001209191-11-003982.txt : 20110119
<SEC-HEADER>0001209191-11-003982.hdr.sgml : 20110119
<ACCEPTANCE-DATETIME>20110119192227
ACCESSION NUMBER:		0001209191-11-003982
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20110114
FILED AS OF DATE:		20110119
DATE AS OF CHANGE:		20110119

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Thompson John David
		CENTRAL INDEX KEY:			0001423891

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34877
		FILM NUMBER:		11537007

	MAIL ADDRESS:	
		STREET 1:		SYMANTEC CORPORATION
		STREET 2:		20330 STEVENS CREEK BLVD.
		CITY:			CUPERTINO
		STATE:			CA
		ZIP:			95014

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CoreSite Realty Corp
		CENTRAL INDEX KEY:			0001490892
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1050 17TH STREET
		STREET 2:		SUITE 800
		CITY:			DENVER
		STATE:			CO
		ZIP:			80265
		BUSINESS PHONE:		(866) 777-2673

	MAIL ADDRESS:	
		STREET 1:		1050 17TH STREET
		STREET 2:		SUITE 800
		CITY:			DENVER
		STATE:			CO
		ZIP:			80265
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c11221_4x0.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-01-14</periodOfReport>

    <issuer>
        <issuerCik>0001490892</issuerCik>
        <issuerName>CoreSite Realty Corp</issuerName>
        <issuerTradingSymbol>COR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001423891</rptOwnerCik>
            <rptOwnerName>Thompson John David</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1050 17TH STREET, SUITE 800</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80265</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-01-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>23</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>23</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2523</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each Restricted Stock Unit (&quot;RSU&quot;) represents the right to receive one share of Common Stock. The reporting person also holds a tandem Dividend Equivalent (&quot;DE&quot;) for each RSU held, which gives the reporting person the right to receive, upon the payment of any ordinary quarterly cash dividend paid to holders of Common Stock,  an equivalent payment in the form of additional RSUs and DEs.</footnote>
        <footnote id="F2">The RSUs are payable upon the reporting person's termination of service as a director and have no expiration date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Erick H. Bromfield, attorney-in-fact</signatureName>
        <signatureDate>2011-01-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----