Dallas (/ˈdæləs/), officially the City of Dallas, is a city in the U.S. state of Texas and the seat of Dallas County, with portions extending into Collin, Denton, Kaufman and Rockwall counties. With an estimated 2017 population of 1,341,075, it is the ninth most-populous city in the U.S. and third in Texas after Houston and San Antonio. It is also the eighteenth most-populous city in North America as of 2015. Located in North Texas, the city of Dallas is the main core of the largest metropolitan area in the Southern United States and the largest inland metropolitan area in the U.S. that lacks any navigable link to the sea. It is the most populous city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the country at 7.3 million people as of 2017. The city's combined statistical area is the seventh-largest in the U.S. as of 2017, with 7,846,293 residents.