Washington is a city in Washington County, Pennsylvania, United States, and part of the Pittsburgh Metro Area. The population was 13,663 at the 2010 census. It is the county seat of Washington County and is located in the southwestern part of the state.
Washington is located at 40°10′30″N 80°15′2″W / 40.175°N 80.25056°W / 40.175; -80.25056 (40.174959, -80.250634).
According to the United States Census Bureau, the city has a total area of 3.3 square miles (8.5 km²), all of it land.