Unionville is a village in Tuscola County in the U.S. state of Michigan. The population was 508 at the 2010 census. The village is located in the northwestern corner of Columbia Township.

Tuscola County is a county in the Thumb region of the U.S. state of Michigan. As of the 2020 census, the population was 53,323. The county seat is Caro. The county was created by Michigan Law on April 1, 1840, from land in Sanilac County and attached to Saginaw County for administrative purposes. The Michigan Legislature passed an act on March 2, 1850, that empowered the county residents to organize governmental functions.