Houston is the fourth-largest city in the United States of America, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of 656.3 square miles (1,700 km2). Houston is the seat of Harris County and the economic center of Houston–Sugar Land–Baytown, which is the fifth-largest metropolitan area in the United States, with 6.08 million people as of July 1st, 2011.