Union County was carved from Cherokee County territory during the Georgia Land Lottery of 1832. Originally inhabited by Native Americans, the area became more desirable to white settlers with the discovery of gold in the 1820s.

The Union Party, a political group that supported removing the Indians and opening the area to white settlers, is the probable inspiration for the county’s name. Upon entering the town of Blairsville, Georgia, one can see a plaque crediting John Thomas (former Justice of the Inferior Court and serving Union County in the Georgia House of Representatives in 1833) for giving the county the name of Union. When asked to suggest a name, he is reported to have said, “Name it Union, for none but union-like men reside in it.” Since the county was founded almost 30 years before the U.S. Civil War, Union County obviously was not named in sympathy for the North, as is sometimes thought. County residents, however, were largely pro-Union in the years leading up to the war, as was true of much of Georgia’s mountainous north, and the county’s delegates to the state convention of 1861 voted against secession. When the state seceded, most Union County residents supported the Confederacy, and the majority of its Civil war Soldiers fought on the Confederate side, although a significant minority fought for the Union. According to the Atlanta Journal-Constitution, the county’s memorial to its generations of war dead may be the only one in the South that specifically includes homage to Union soldiers and to American Indians who fought white settlement.

Union County is often called “The Top of Georgia” because Brasstown Bald is partly in the county.