Cozen O’Connor has continued its focus on the Washington, D.C., market, adding 15 lawyers and government relations professionals from Sher & Blackwell, an international transportation and government affairs law firm based in the city.

The move nearly doubles Cozen O’Connor’s presence in the nation’s capital and comes on the heels of the firm’s addition of an antitrust and international trade practice there. The Sher & Blackwell group will join effective Sept. 1, 2010.