Indigenous peoples inhabited the location dating to as early as 10,000 BC. In 1818, the Delaware relinquished their tribal lands in the Treaty of St. Mary's. In 1821, Indianapolis was launched as a planned metropolis for the new seat of Indiana's state govt. The town was platted by Alexander Ralston and Elias Pym Fordham on a one-square-mile (two.6 km2) grid next to the White River. Completion of