Union is a town in Vernon County, Wisconsin, United States.

According to the United States Census Bureau, the town has a total area of 35.8 square miles (92.6 km2), all of it land.

There were 244 housing units at an average density of 6.8 per square mile (2.6/km2).

The racial makeup of the town was 99.44% White, 0.19% Native American, 0.19% Asian, and 0.19% from two or more races.

17.0% of all households were made up of individuals, and 10.9% had someone living alone who was 65 years of age or older.