Fort Washington is a census-designated place and suburb of Philadelphia in Montgomery County, Pennsylvania, United States. The population was 5,446 at the 2010 census.

Montgomery County, colloquially referred to as Montco, is a county in the Commonwealth of Pennsylvania. As of the 2020 census, the population of the county was 856,553, making it the third-most populous county in Pennsylvania after Philadelphia and Allegheny counties. The county is part of the Southeast Pennsylvania region of the state.