With an estimated population of 2,257,926 in 2009, Houston is the largest city in Texas. The city sits to the northwest of Galveston Bay in the Gulf of Mexico. Houston is home to the Texas Medical Center, which is the world's largest collection of health care and medical research establishments, and to the Johnson Space Center, home to NASA's Mission Control. The city is served by three airports, by Amtrak and is the hub of nine major highways, as well as being a major eastern U.S. port.
San Antonio is Texas' second largest city, having an estimated population of 1,373,668 in 2009. The city lies about 200 miles west of Houston and on the edge of the humid subtropical climate, experiencing both dry and humid conditions depending on the current prevailing wind. San Antonio is home to one of America's largest military concentrations, with three Air Force bases and a military reservation. The city's Henry B. Gonzalez Convention Center hosts more than 300 events each year, accounting for more than 750,000 convention delegates from all over the globe.
According to the U.S. Census Bureau the 2009 population of Dallas was 1,299,542, making it Texas' third largest city. The city is a major home to telecommunications companies; Telecom Corridor in the northern suburb of Richardson houses nearly 6,000 companies. Many of the country's major companies have their corporate headquarters in Dallas. Dallas is home to eight major tertiary education institutions and, of course, to the Dallas Cowboys, winners of no less than five Super Bowls.
The population of Texas' fourth largest city, Austin, was estimated as being 786,386 in 2009, according to the U.S. Census Bureau. Austin lies some 80 miles north of San Antonio and about 160 miles west of Houston. A large number of high-tech companies have migrated to Austin during the last 20 years, because housing costs are so much less than those of Silicon Valley. This migration has caused the city to be called Silicon Hills. Austin sits astride the Colorado River, which has three dammed reservoirs within the city limits.
