Midland is a city in and the county seat of Midland County, Texas, United States, on the Southern Plains of the state's western area. A small portion of the city extends into Martin County. At the 2010 census, the population of Midland was 111,147, and a 2013 estimate of 123,933 making it the twenty-fifth most populous city in the state of Texas. Due to the oil boom in Midland, certain officials have estimated the population to be hovering around 155,000 to 165,000. The population of the Midland metropolitan area, composed of Midland County, grew 4.6 percent to 151,662 between July 1, 2011, and July 1, 2012, according to the U.S. Census Bureau. It is the principal city of the Midland, Texas Metropolitan Statistical Area, which includes all of Midland County.