Indianapolis is the capital and largest city of the U.S. state of Indiana and the seat of Marion County. It is in the East North Central region of the Midwestern United States. The city covers 372 square miles (963.5 km²) with an estimated population of 853,173 in 2015, making it the second most populous city in the Midwest, after Chicago, and 14th largest in the United States. The city is the economic and cultural center of the Indianapolis metropolitan area, home to 2 million people, the 34th most populous metropolitan statistical area in the United States. Its combined statistical area ranks 26th, with 2.4 million inhabitants. Indianapolis anchors the 26th largest economic region in the United States.Founded in 1821 as a planned city for the new seat of the government of Indiana, Indianapolis was platted by Alexander Ralston and Elias Pym Fordham on a 1sqmi grid adjacent to the White River. The city grew beyond the Mile Square, as completion of the National Road and advent of the railroad solidified the city's position as a manufacturing and transportation hub. Indianapolis is within a single-day drive of 70 percent of the nation's population, lending to its nickname as the "Crossroads of America." Indianapolis' economy is based on business services, transportation and logistics, education, financial services, hospitality and tourism, and distribution services. Indianapolis has developed niche markets in amateur sports and auto racing. The city hosts numerous events annually, most notably the Indianapolis 500, the world's largest single-day sporting event.