The Town[3] of Union is located in Rock County, Wisconsin, United States.

As of the census[2] of 2000, there were 1,860 people, 693 households, and 539 families residing in the town.

There were 718 housing units at an average density of 21.1 per square mile (8.1/km2).The racial makeup of the town was 97.47% White, 0.16% African American, 0.22% Native American, 0.70% Asian, 0.43% from other races, and 1.02% from two or more races.

There were 693 households, out of which 39.8% had children under the age of 18 living with them, 67.0% were married couples living together, 6.2% had a female householder with no husband present, and 22.1% were non-families.

17.0% of all households were made up of individuals, and 4.3% had someone living alone who was 65 years of age or older.