As filed with the Securities and Exchange Commission on July 1, 2011
 Registration Statement No. 333-
   UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
 Washington, D.C. 20549
 FORM S-8
 REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
 First Potomac Realty Trust
  Maryland
    
    37-1470730(State or other jurisdiction of incorporation or
    
    (I.R.S. Employer Identification No.)organization)
 7600 Wisconsin Avenue, 11 th Floor
Bethesda, Maryland 20814
 First Potomac Realty Trust 2009 Equity Compensation Plan
 Joel F. Bonder
Executive Vice President and General Counsel
First Potomac Realty Trust
7600 Wisconsin Avenue, 11 th Floor
Bethesda, Maryland 20814
(301) 986-9200
 Copy to:  David P. Slotkin
Hogan Lovells US LLP
Columbia Square
555 Thirteenth Street, NW
Washington, DC 20004
(202) 637-5600
  Large Accelerated Filer o
    
    Accelerated Filer þ
    
    Non-Accelerated Filer o
    
    Smaller reporting company o(Do not check if smaller reporting company)
 CALCULATION OF REGISTRATION FEE
 Proposed
    
    
    ProposedAmount to be
    
    
    maximum offering
    
    
    maximum aggregate
    
    
    Amount ofTitle of securities to be registered
    
    
    Registered(1)
    
    
    price per share(2)
    
    
    offering price (2)
    
    
    registration fee(2)Common shares of beneficial
interest, par value $0.001 per
share
    
    
    4,500,000 shares
    
    
    $
    15.12
    
    
    
    $
    68,040,000
    
    
    
    $
    7,900
 (1)
    
    Pursuant to Rule 416(a) of the Securities Act of 1933, as amended (the
Securities Act), this Registration Statement shall also cover, in
addition to the number of common shares of beneficial interest
(common shares) shown above, an indeterminate number of common
shares that may become issuable under the First Potomac Realty Trust
2009 Equity Compensation Plan (the Plan) by reason of any stock
dividend, stock split, recapitalization, or other similar transaction
effected without the receipt of consideration which results in an
increase in the number of the Registrants outstanding common shares.(2)
    
    Estimated solely for the purpose of computing the registration fee. In
accordance with Rules 457(c) and 457(h) under the Securities Act, the
maximum offering price per share and maximum aggregate offering price
shown are based on the average of the high and low sales prices
reported for the Registrants common shares on the New York Stock
Exchange on June 29, 2011, which was $15.12 per share.




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EXPLANATORY NOTE
  PART I
INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
  PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
 Item 3. Incorporation of Documents by Reference.
  
    
    The Companys Annual Report on Form 10-K for the year ended December 31, 2010;
    
    The Companys Quarterly Report on Form 10-Q for the quarterly period ended March 31,
2011;
    
    The Companys Current Reports on Form 8-K filed with the SEC on January 11, 2011,
January 14, 2011, January 19, 2011, January 28, 2011, February 28, 2011, March 29, 2011,
May 13, 2011, May 23, 2011, June 13, 2011,
June 22, 2011 and July 1, 2011; and
    
    The Companys Registration Statement on Form 8-A, which incorporates by reference the
description of the Companys common shares from our Registration Statement on Form S-11
(Reg. No. 333-107172), and all amendments, prospectuses or reports filed for the purpose of
updating such description.




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Item 8. Exhibits.
 ExhibitNo.
    
    Description5.1
    
    
    Opinion of Hogan Lovells US LLP as to the legality of the securities being registered.10.1
    
    
    First Potomac Realty Trust 2009 Equity Compensation Plan (incorporated by reference
to Exhibit A to the Companys Definitive Proxy Statement, filed with the SEC on April
8, 2009).10.2
    
    
    Amendment No. 1 to the First Potomac Realty Trust 2009 Equity Compensation Plan
(incorporated by reference to Exhibit 10.1 to the Companys Current Report on Form
8-K/A, filed with the SEC on May 27, 2010).10.3
    
    
    Amendment No. 2 to the First Potomac Realty Trust 2009 Equity Compensation Plan
(incorporated by reference to Exhibit 10.1 to the Companys Current Report on Form
8-K, filed with the SEC on May 23, 2011).23.1
    
    
    Consent of KPMG LLP.23.2
    
    
    Consent of Hogan Lovells US LLP (included in Exhibit 5.1).24.1
    
    
    Power of Attorney (included on signature page).




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SIGNATURES
  First Potomac Realty TrustBy:
    /s/ Barry H. BassBarry H. BassExecutive Vice President
and Chief Financial Officer   /s/ Douglas J. Donatelli

Douglas J. Donatelli
    
    Chairman of the Board of
Trustees and 
Chief Executive
Officer

(Principal Executive Officer)
    
    July 1, 2011/s/ Barry H. Bass

Barry H. Bass
    
    Executive Vice President and 

Chief Financial Officer

(Principal Financial Officer)
    
    July 1, 2011/s/ Michael H. Comer

Michael H. Comer
    
    Senior Vice President and

Chief Accounting Officer

(Principal Accounting Officer)
    
    July 1, 2011/s/ Robert H. Arnold

Robert H. Arnold
    
    Trustee
    
    July 1, 2011Richard
B. Chess
    
    TrusteeJ.
Roderick Heller, III
    
    Trustee/s/ R. Michael McCullough

R. Michael McCullough
    
    Trustee
    
    July 1, 2011/s/ Alan G. Merten

Alan G. Merten
    
    Trustee
    
    July 1, 2011Terry
L. Stevens
    
    Trustee




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EXHIBIT INDEX
 ExhibitNo.
    
    Description5.1
    
    
    Opinion of Hogan Lovells US LLP as to the legality of the securities being registered.10.1
    
    
    First Potomac Realty Trust 2009 Equity Compensation Plan (incorporated by reference
to Exhibit A to the Companys Definitive Proxy Statement, filed on April 8, 2009).10.2
    
    
    Amendment No. 1 to the First Potomac Realty Trust 2009 Equity Compensation Plan
(incorporated by reference to Exhibit 10.1 to the Companys Current Report on Form
8-K/A, filed with the SEC on May 27, 2010).10.3
    
    
    Amendment No. 2 to the First Potomac Realty Trust 2009 Equity Compensation Plan
(incorporated by reference to Exhibit 10.1 to the Companys Current Report on Form
8-K, filed with the SEC on May 23, 2011).23.1
    
    
    Consent of KPMG LLP.23.2
    
    
    Consent of Hogan Lovells US LLP (included as Exhibit 5.1).24.1
    
    
    Power of Attorney (included on signature page).