Indigenous peoples inhabited the area dating to approximately 2000 BC. In 1818, the Delaware relinquished title to their tribal lands in the Treaty of St. Mary's. In 1821, Indianapolis was founded as a planned city for the new seat of Indiana's state government. The city was platted by Alexander Ralston and Elias Pym Fordham on a 1 square mile (2.6 km2) grid adjacent to the White River. Completion of the National Road and the advent of the railroad later solidified the city's position as a manufacturing and transportation hub.
Anchoring the 25th largest economic region in the U.S., the city's economy is based primarily on finance and insurance, manufacturing, professional and business services, education and health care, government, and wholesale trade. Indianapolis is within a single-day drive of 70 percent of the nation's population, lending to one of its nicknames as the "Crossroads of America". Indianapolis has developed niche markets in amateur sports and auto racing. The city is perhaps best known for annually hosting the world's largest single-day sporting event, the Indianapolis 500.
Indianapolis is home to two major sports clubs, the Indiana Pacers of the National Basketball Association and the Indianapolis Colts of the National Football League. The city's philanthropic community has been instrumental in the development of its cultural institutions and collections, including the world's largest children's museum, nation's largest privately funded zoo, historic buildings and sites, and public art. Indianapolis is headquarters for the American Legion and home to a significant collection of monuments dedicated to veterans and war dead, the most in the U.S. outside of Washington, D.C. Since the 1970 city-county consolidation, known as Unigov, local government administration operates under the direction of an elected 25-member city-county council headed by the mayor. Indianapolis is considered a "high sufficiency" world city.
The name Indianapolis is derived from the state's name, Indiana (meaning "Land of the Indians", or simply "Indian Land"), and polis, the Greek word for city. Jeremiah Sullivan, justice of the Indiana Supreme Court, is credited with coining the name. Other names considered were Concord, Suwarrow, and Tecumseh.
In 1816, the year Indiana gained statehood, the U.S. Congress donated four sections of federal land to establish a permanent seat of state government. Two years later, under the Treaty of St. Mary's (1818), the Delaware relinquished title to their tribal lands in central Indiana, agreeing to leave the area by 1821. This tract of land, which was called the New Purchase, included the site selected for the new state capital in 1820.