Washington County, Ohio

Washington County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 61,778. Its county seat is Marietta. The county, the oldest in the state, is named for George Washington.Washington County comprises the Marietta, OH Micropolitan Statistical Area, which is also included in the Parkersburg-Marietta-Vienna, WV-OH Combined Statistical Area.GeographyAccording to the U.S. Census Bureau, the county has a total area of, of which is land and (1.3%) is water. It is the fifth-largest county in Ohio by land area.Washington County's southern and eastern boundary is the Ohio River. The Muskingum River, Little Muskingum River, Duck Creek, and the Little Hocking River flow through the county to the Ohio River.Adjacent countiesNoble County (north)Monroe County (northeast)Tyler County, West Virginia (east)Pleasants County, West Virginia (southeast)Wood County, West Virginia (south)Athens County (southwest)Morgan County (northwest)