Thomas Lyon Hamer (July 1800 – December 2, 1846) was a United States Democratic congressman and soldier. Hamer was born in July, 1800 in Northumberland County, Pennsylvania. He was a school teacher before being admitted to the bar in 1821. He was an Ohio Presidential elector in 1828 for Andrew Jackson. He was buried in his hometown of Georgetown. A few miles away the town of Hamersville, Ohio was named in his honor. Also named in his honor is Hamer Township in neighboring Highland County, Ohio.