6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

FORM 6-K

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of May 2016

Commission File No. 1-31690

TransCanada Corporation

(Translation of Registrant's Name into English)

450 – 1 Street S.W., Calgary, Alberta, T2P 5H1, Canada

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F                      ¨                      Form 40-F                      þ

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ¨

Exhibit 99.1 to this report, furnished on Form 6-K, is furnished, not filed, and will not be incorporated by reference into any registration statement filed by the registrant under the Securities Act of 1933, as amended.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: May 18, 2016

TRANSCANADA CORPORATION
By:	/s/ Christine R. Johnston
	Christine R. Johnston
	Vice-President, Law and Corporate Secretary

EXHIBIT INDEX

99.1 A copy of the registrant’s News Release dated May 17, 2016.

EX-99.1

EXHIBIT 99.1

NewsRelease

TransCanada Announces Early Termination of

Hart-Scott-Rodino Waiting Period for Anticipated Columbia Pipeline Group Acquisition

CALGARY, Alberta - May 17, 2016 - News Release - TransCanada Corporation (TSX, NYSE: TRP) (TransCanada) today announced that the waiting period under the Hart-Scott-Rodino Anti-Trust Improvements Act (HSR Act) applicable to TransCanada’s proposed acquisition of Columbia Pipeline Group Inc. (NYSE:CPGX) (Columbia) was terminated early by the United States Federal Trade Commission on May 17, 2016.

Termination of the HSR waiting period satisfies one of the conditions to the closing of the proposed acquisition. The acquisition remains subject to the approval of Columbia’s stockholders scheduled for June 22, 2016.

TransCanada and Columbia anticipate that the closing of the transaction will be effective by July 1, 2016.

With more than 65 years' experience, TransCanada is a leader in the responsible development and reliable operation of North American energy infrastructure including natural gas and liquids pipelines, power generation and gas storage facilities. TransCanada operates a network of natural gas pipelines that extends more than 66,400 kilometres (41,300 miles), tapping into virtually all major gas supply basins in North America. TransCanada is one of the continent's largest providers of gas storage and related services with 368 billion cubic feet of storage capacity. A growing independent power producer, TransCanada owns or has interests in over 10,500 megawatts of power generation in Canada and the United States. TransCanada is developing one of North America's largest liquids delivery systems. TransCanada's common shares trade on the Toronto and New York stock exchanges under the symbol TRP. Visit TransCanada.com and our blog to learn more, or connect with us on social media and 3BL Media.

FORWARD LOOKING INFORMATION

This publication contains certain information that is forward-looking and is subject to important risks and uncertainties (such statements are usually accompanied by words such as "anticipate", "expect", "believe", "may", "will", "should", "estimate", "intend" or other similar words). Forward-looking statements in this document are intended to provide TransCanada security holders and potential investors with information regarding TransCanada and its subsidiaries, including management's assessment of TransCanada's and its subsidiaries' future plans and financial outlook. All forward-looking statements reflect TransCanada's beliefs and assumptions based on information available at the time the statements were made and as such are not guarantees of future performance. Readers are cautioned not to place undue reliance on this forward-looking information, which is given as of the date it is expressed in this news release, and not to use future-oriented information or financial outlooks for anything other than their intended purpose. TransCanada undertakes no obligation to update or revise any forward-looking information except as required by law. For additional information on the assumptions made, and the risks and uncertainties which could cause actual results to differ from the anticipated results, refer to TransCanada’s First Quarter Report to Shareholders dated April 28, 2016 and 2015 Annual Report on our website at www.transcanada.com or filed under TransCanada's profile on SEDAR at www.sedar.com and with the U.S. Securities and Exchange Commission at www.sec.gov.

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EXHIBIT 99.1

Media Enquiries:

Mark Cooper / Terry Cunha

403.920.7859 or 800.608.7859

TransCanada Investor & Analyst Enquiries:

David Moneta / Stuart Kampel

403.920.7911 or 800.361.6522