Old Shawneetown is a village in Gallatin County, Illinois, United States. As of the 2020 census, the village had a population of 113, down from 193 at the 2010 census. Located along the Ohio River, Shawneetown served as an important United States government administrative center for the Northwest Territory. The village was devastated by the Ohio River flood of 1937. The village's population was moved several miles inland to New Shawneetown.

Gallatin County is a county located in the U.S. state of Illinois. According to the 2020 census, it has a population of 4,946, making it the third-least populous county in Illinois. Its county seat is Shawneetown. It is located in the southern portion of Illinois known locally as Little Egypt. Located at the mouth of the Wabash River, Gallatin County, along with neighboring Posey County, Indiana, and Union County, Kentucky form the tri-point of the Illinois-Indiana-Kentucky Tri-State Area.