Unionville, Ashtabula County, Ohio
Unionville is an unincorporated community on the line between northwestern Harpersfield Township in Ashtabula County and eastern Madison Township in Lake County in the U.S. state of Ohio. Although it is unincorporated, it has a post office, with the ZIP code of 44088. It lies along State Route 84.
The community's location where two counties meet caused the name "Union" to be selected. Unionville is the site of the land office of the Connecticut Western Reserve; it is listed on the National Register of Historic Places.