West Union is a village in Adams County, Ohio, United States, about 55 miles (89 km) southeast of Cincinnati. The population was 3,241 at the 2010 census. It is the county seat of Adams County.
West Union is served by West Union High School, the Adams County/Ohio Valley School District, and the West Union Public Library, a branch of the Adams County Public Library.
West Union was laid out in 1803. A post office called West Union has been in operation since 1805. The village was incorporated in 1859.
West Union is located at 38°47′38″N 83°32′38″W (38.793979, -83.543500).
According to the United States Census Bureau, the village has a total area of 2.83 square miles (7.33 km2), all land.
State Routes 41, 125, and 247 all intersect and run concurrently through the downtown area.
Ironically, West Union lies east of Union, Ohio, a city in Montgomery County approximately 10 miles north of Dayton. West Union and Union are not adjacent to each other, actually being approximately 120 miles from each other.
As of the census 3,421, 1,322 households, and 420 families living in the village. The population density was 1,145.2 inhabitants per square mile (442.2/km2).