Indianapolis is the capital of the U.S. state of Indiana, and the county seat of Marion County, Indiana. It is Indiana's largest city and is the 14th largest city in the U.S., the third largest city in the Midwest (behind Chicago and Detroit), the second most populous state capital (after Phoenix, Arizona), and the most populous state capital east of the Mississippi River. The city is also known as the "Racing Capital of the World" due to the proximity of the Indianapolis Motor Speedway, home of the Indy 500 and Allstate 400 at the Brickyard (formerly known as the "Brickyard 400").