Union City is a borough in Erie County, Pennsylvania, 26 miles (42 km) southeast of Erie. In the twentieth century, there were three large chair factories, planing and grist mills, a powdered milk plant, and several furniture factories. In 1900, 3,104 people lived here, and in 1910, 3,684 people lived here. The population was 3,463 at the 2000 census. It is part of the Erie Metropolitan Statistical Area.