Houston is the largest city in the state of Texas and the fourth-largest in the United States. The city covers more than 600 square miles (1,600 km²) and is the county seat of Harris County—the third-most populous in the country. As of the 2004 U.S. Census estimate, Houston had a population of more than 2 million. The city is at the heart of the Houston–Sugar Land–Baytown metropolitan area, the largest cultural and economic center of the Gulf Coast region and the seventh-largest metropolitan area in the U.S. with a population of 5.3 million in 10 counties.

Houston is world-renowned for its energy (particularly oil) and aeronautics industries, and for its ship channel. The area is also the world's leading center for building oilfield equipment. The Port of Houston ranks first in the country in international commerce and is the sixth-largest port in the world. Second only to New York City in Fortune 500 headquarters, Houston is the seat of the internationally-renowned Texas Medical Center, which contains the world's largest concentration of research and healthcare institutions.

Houston is ranked as one of 11 U.S. world-class cities by the Globalization and World Cities Study Group & Network. The city has a vibrant visual and performing arts scene as Houston is one of the five U.S. cities that offer world-class, year-round resident companies in all major performing arts. In addition, the Houston Theater District is ranked second in the country for the number of theatre seats in a concentrated downtown area per capita. The city is within proximity to beaches on Galveston Island as well as one of the United States's largest concentrations of pleasure boats.