Washington is a city in and the county seat of Washington County, Kansas, United States. As of the 2010 census, the city population was 1,131.
Washington is 39°N 97°W / 39°N 97°W / 39; -97 (39.816877, -97.052503). According to the United States Census Bureau, the city has a total area of 0.9 square miles (2.3 km2), of which, 0.9 square miles (2.3 km2) of it is land and 1.12% is water.
As of the census of 2000, there were 1,223 people, 553 households, and 331 families residing in the city. The population density was 1,395.3 people per square mile (536.6/km²). There were 644 housing units at an average density of 734.7 per square mile (282.6/km²). The racial makeup of the city was 98.94% White, 0.08% African American, 0.25% Native American, 0.25% from other races, and 0.49% from two or more races. Hispanic or Latino of any race were 0.57% of the population.