Union is a village in McHenry County, Illinois, United States.

According to the U.S. Census Bureau, Union has a total area of 0.84 square miles (2.18 km2), all land.

[11] Union is home to the Illinois Railway Museum and the McHenry County Historical Society.

[12] It was formerly the home of Donley's Wild West Town amusement park, now closed.

For cable television, Union is served by Charter Communications instead of Comcast, like the rest of the Chicago Metropolitan Area.