Unionville is a village in Tuscola County in the U.S. state of Michigan. The population was 605 at the 2000 census. The village is located in the northwestern corner of Columbia Township.
As of the census of 2000, there were 605 people, 231 households, and 170 families residing in the village. The population density was 652.2 per square mile (251.2/km²). There were 246 housing units at an average density of 265.2 per square mile (102.1/km²). The racial makeup of the village was 97.02% White, 0.83% Asian, 0.33% from other races, and 1.82% from two or more races. Hispanic or Latino of any race were 2.81% of the population.
There were 231 households out of which 37.2% had children under the age of 18 living with them, 58.9% were married couples living together, 11.7% had a female householder with no husband present, and 26.4% were non-families. 22.9% of all households were made up of individuals and 10.0% had someone living alone who was 65 years of age or older. The average household size was 2.62 and the average family size was 3.11.