Houston is the most populous city in the U.S. state of Texas and the Southern United States. It is the fourth-most populous city in the United States, with a population of 2.3 million at the 2020 census. The Greater Houston metropolitan area, at 7.8 million residents, is the fifth-most populous metropolitan area in the nation and second-most populous in Texas. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, Houston is the county seat of Harris County. Covering a total area of 640.4 square miles (1,659 km²), it is the ninth largest city in the country and the largest whose municipal government is not consolidated with a county, parish, or borough. Although primarily located within Harris County, portions of the city extend into Fort Bend and Montgomery counties. Houston also functions as the southeastern anchor of the Texas Triangle megaregion.