Indianapolis /ˌɪndiəˈnæpɵlɨs/ (abbreviated Indy /ˈɪndi/) is a city located in the Great Lakes region of the United States. Indianapolis is the capital of the US state of Indiana, and also the county seat of Marion County, Indiana. As of the 2010 Census, the city's population is 829,718. It is the twelfth largest city in the United States, and one of the fastest growing metropolitan areas in the United States.