Washington County is the name of 30 counties and one parish in the United States of America, all named after George Washington, revolutionary war general and first President of the United States. It is the most common county name in the United States. The following 32 states and one district have or had a Washington County:
- Washington County, South Dakota, a former county (1883–1943) that was divided in 1943 because of financial troubles in South Dakota
- Washington County, District of Columbia, a former county of the District of Columbia that was abolished in 1871 along with all of the other counties in that District
- Washington District, North Carolina, a district and later county in North Carolina that became part of Tennessee in 1796.
- List of Washington counties, counties in the state of Washington
- Washington County (album), a 1970 album by Arlo Guthrie
- Washington County School District (disambiguation)