Clarksville is a town in Clark County, Indiana, United States, along the Ohio River and is a part of the Louisville Metropolitan area. The population was 22,333 at the 2020 census. The town was founded in 1783 by early resident George Rogers Clark at the only seasonal rapids on the entire Ohio River, it is the oldest American town in the former Northwest Territory. The town is home to the Colgate clock, one of the largest clocks in the world and the Falls of the Ohio State Park, home to the world's largest exposed Devonian period fossil bed.

George Rogers Clark was an American military officer and surveyor from Virginia who became the highest-ranking Patriot military officer on the northwestern frontier during the Revolutionary War. He served as leader of the Virginia militia in Kentucky throughout much of the war. He is best known for his captures of Kaskaskia in 1778 and Vincennes in 1779 during the Illinois campaign, which greatly weakened British influence in the Northwest Territory and earned Clark the nickname of "Conqueror of the Old Northwest". The British ceded the entire Northwest Territory to the United States in the 1783 Treaty of Paris.