Houston, TX is the capital of Texas and the fourth most populous city in the United States. It is the largest city in the U.S. state of Texas and the county seat of Harris County. It is the most populous city in the Houston–The Woodlands–Sugar Land, TX MSA and the most populous city in the U.S. state of Texas. Houston is the most populous city in the U.S. state of Texas, the most populous city in the U.S. state of Texas, and the fourth most populous city in the United States. It is the largest city in the U.S. state of Texas and the fourth largest city in the U