Albuquerque ( /ˈælbəkɜrkiː/) is the largest city in the state of New Mexico, United States. It is the county seat of Bernalillo County and is situated in the central part of the state, straddling the Rio Grande. The city population was 545,852 as of the 2010 Census and ranks as the 32nd-largest city in the U.S. As of June 2007, the city was the sixth fastest-growing in America. It has a metropolitan population of 887,077 as of the 2010 Census. Albuquerque is the 57th-largest United States metropolitan area. The Albuquerque MSA population includes the city of Rio Rancho.