Union is a town in Knox County, Maine, United States.

[2] It is home to the Matthews Museum of Maine Heritage and annual Union Fair.

Union was part of a tract of land called the Muscongus Patent, a grant made March 2, 1629, by the Plymouth Council to John Beauchamp and Thomas Leverett.

The first white settlers by the names of Anderson, Malcolm, and Crawford, arrived in 1772.

On May 3, 1786, it was organized as the Plantation of Sterlingtown, and on October 20, 1786, the town was incorporated and named Union.

The town had mills operated by water power at the outlets of ponds.

Factories at Union produced carriages, cultivators, leather, harness, boots and shoes.

East Union had a lumbermill, in addition to a chair and table factory.

Union was the subject of the 1940 historical novel, Come Spring, by author Ben Ames Williams.

Coggans Hill, elevation 817 feet (249 meters) above sea level, is the highest point in the town.