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Exhibit 10.11

6715 Kenilworth Avenue Partnership
1015 31st Street, NW
Washington, DC 20007

Reference: Lease Agreement dated Sept. 1, 2000
Extension of Lease Agreement dated August 1, 2001
Amendment to Lease Agreement dated Oct. 29, 2001
Amendment to Lease Agreement dated May 1, 2002
Amendment to Lease Agreement dated July 24, 2002

March 1, 2003 Amendment to Lease Agreement

        Cogent Communications, Inc. (Tenant) and 6715 Kenilworth Avenue
Partnership (Landlord) hereby agree to modify the square foot rental and the
associated monthly and aggregate rental payment amounts pertaining to the Lease
Term commencing September 1, 2002 and expiring August 31, 2003 of the Lease
Agreement dated September 1, 2001, as amended (Lease Agreement), so that Tenant
will rent 15,369 square feet at a Fixed Annual Rent of $24 per square foot
($368,856 on an annualized basis), payable in six (6) equal monthly installments
of $30,738 for the remainder of the current Lease Term, as indicated below:

Rent Payment       1015 31st St
 
 
 
 
 
 
  Floor

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    Square Feet

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3       0     4       5,123     5       5,123     6       5,123          

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Total Sq. Feet       15,369          

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Total Annual Rent     $ 368,856          

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Total Monthly Rent     $ 30,738          

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Except as amended herein, the Lease Agreement, as amended, shall remain in full
force and effect.

TENANT: Cogent Communications, Inc
 
 
 
 
  /s/Thaddeus G. Weed

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Thaddeus G. Weed
Vice President, Controller    
 
 
  LANDLORD: 6715 Kenilworth Avenue Partnership
 
 
  /s/Dave Schaeffer

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Dave Schaeffer
General Partner
   

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Exhibit 10.11