Trafford is a borough in Allegheny and Westmoreland counties in the U.S. state of Pennsylvania. Located near Pittsburgh in western Pennsylvania, the borough lies primarily in Westmoreland County; only a small portion extends into Allegheny County. It was incorporated in 1904 from the northernmost corner of North Huntingdon Township, and was named by George Westinghouse for Trafford near Manchester, England. The population was 3,174 at the 2010 census. Of this, 3,113 were in Westmoreland County, and only 61 were in Allegheny County.