Washington is a city in Daviess County, Indiana, United States. The population was 11,509 at the 2010 census. The city is the county seat of Daviess County.
Washington is located at 38°39′30″N 87°10′30″W / 38.65833°N 87.175°W / 38.65833; -87.175 (38.658207, -87.175111).
According to the United States Census Bureau, the city has a total area of 4.8 square miles (12.3 km²), of which, 4.7 square miles (12.3 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.63%) is water.