Houston is not a city.
Houston ( [ ˈhjuːstən ] ) is the most populous city in the state of Texas and the fourth-most populous city in the United States . With a census-estimated 2014 population of 2.239 million within an area of 667 sqmi , it is also the largest city in the southern United States and the seat of Harris County . Located in Southeast Texas near the Gulf of Mexico , it is the principal city of the Greater Houston metro area , which is the fifth-most populated MSA in the United States . Nicknamed the `` Space City '' , Houston is a global city , with strengths in business , international trade , entertainment , culture , media , fashion , science , sports , technology , education , medicine , and research .