In 1818, the Lenape people relinquished their tribal lands in the Treaty of St. Mary's, setting the stage for the establishment of Indianapolis four years later. The Indiana state government designated Indianapolis as a planned city in 1821, with Alexander Ralston and Elias Pym Fordham plotting it on a 2.6 km (1 square mile) grid along the White River. The city quickly became a hub for religious congregations, with Baptists, Presbyterians, and Methodists establishing the first churches in the 1820s.
Other denominations, including Episcopalians, Disciples of Christ, Lutherans, Catholics, Congregationalists, Quakers, Universalists, Unitarians, and Jewish congregations soon followed. The Indianapolis Turngemeinde (185), or Turners, merged with other German clubs and became known as the Indianapolis Social Turnverein. Indianapolis has been closely associated with politics since its selection as the seat of the Indiana government in the 1820s. It also became a major railroad transportation hub for the region and a center for civic and cultural affairs. The Indiana State Fair has been held annually in Indianapolis since 1852, and NASCAR's 500 mile Memorial Day race, the Indianapolis 500, was first held in 1911. The city was founded on land that had previously been inhabited by the Lenape nation.
In addition to newspaper reports, details of Indianapolis's early history are documented in the diary of Calvin Fletcher, one of the first prominent residents who was actively involved in the city's civic and business affairs. In 1970, the Unigov bill was passed by the Indiana General Assembly. This bill unified the city and county's budgetary functions and enabled the consolidation of law enforcement agencies such as the Indianapolis Metropolitan Police Department and Marion County Sheriff's Department. It also allowed for consolidation of fire departments based on approval from affected parties.