Houston is the most populated city in Texas and the fourth-largest city in the country, with an estimated population of 2.3 million people. Located in Harris County, the total area of Houston is 637 square miles, making it the largest city in the United States by area.

Houston became the state's leading port in the 19th century after devastating hurricanes and flooding destroyed the port facilities of Galveston. The deep-water port, which ranks second and third in the United States in terms of access to shipping worldwide, has made Houston one of the largest and most important ports in Texas and the second-largest port in America.

The Second World War brought the shipbuilding and petrochemical industries to Houston, and chemicals remained important even after the war. In the Houston area, several refineries were built that served as the basis for the wars at different times.

During the Civil War, businessmen began a campaign to dredge wells and canals to form the Houston River and its tributary to the Gulf of Mexico. Houston was also the rail hub of Southeast Texas, with five lines running from Fort Worth to San Antonio and then on to Corpus Christi. Other roads began in the early 20th century, such as the Katy Trail and the Galveston-Houston Trail.

Oil companies decided to locate refineries in Houston's shipping channel, where they were safe from Gulf storms. At the beginning of the 20th century, oil companies like Exxon, BP, Chevron, and Shell had their oil and gas operations in Texas and hid from the Gulf of Mexico by going in the opposite direction.

With temperatures averaging 43 degrees in winter and 94 degrees in summer, Houston became one of the most air-conditioned cities in North America.

Houston has been nicknamed the "Bayou City," "Space City," and "H-Town," and in recent years, it has seen an increase in the medicine and research industries. The city's Museum District includes 19 museums, galleries, and community spaces and attracts more than 7 million visitors a year.