The area was first surveyed by Robert Clark in 1826, and Isaiah Bennett purchased the first plot of land from the government in 1831.

Justus Goodwin bought a large piece of Bennett's land in 1833, and he built a mill and became the first postmaster when a post office began operating on November 9, 1834.

[6] The slaves seeking refuge were taken into a home built around 1840 by Mr. Zimmerman, who arrived in Union City from Fairfield, Connecticut, in the spring of 1838.

In September 1839, Zimmerman returned to Union City with his family; he soon built a wagon factory, blacksmith shop, and a Greek Revival house.

Outraged by the institution of slavery, Zimmerman became a stationmaster for the Underground Railroad, hiding escaped slaves in his house and assisting them in their flight to Canada and freedom.

The home is on the list of Michigan State Historic Sites and is located at 119 East High Street.

[7][8] In the early 1920s Union City built a hydroelectrical plant to deliver cheaper electricity to the town.

By 1923 Riley Dam was constructed on nearby St. Joseph River, and the backwater forms Union Lake.

Her home, the Meteor Ridge Farm, formerly called The Plantation, was built in 1859 or 1860 and also served as a stop on the Underground Railroad, even receiving a personal visit from President Lincoln.

[2] The vast majority of the village's area and population is located within Union Township in Branch County.

The remaining 0.10 square miles (0.26 km2) of area is part of Burlington Township in Calhoun County to the north.