Texas is a state in the South and Southwest regions of the United States of America. With an area of 268,581 square miles (695,622 km²) and a population of 22.8 million, Texas is the second-largest U.S. state in both area and population, and the largest state in the contiguous 48 states in area. The state name derives from a word in a Caddoan language of the Hasinai, táyshaʔ, tecas (or tejas, as the Spaniards spelled it), meaning "those who are friends," friends or allies. Spanish explorers mistakenly applied the word to the people and their location.

Texas joined the United States in 1845 as the 28th state, after nearly 10 years as the Republic of Texas—an independent country. Texas historically had a "larger than life" reputation, especially in cowboy films. The term "Texas sized" is used to describe something larger than average, and large geographic areas are often described in terms of the size of Texas. It is the southernmost part of the Great Plains, which ends in the south against the folded Sierra Madre Oriental of Mexico. It is in the south-central part of the United States of America. It is considered to form part of the U.S. South and also part of the U.S. Southwest.

In 2005 Texas had a gross state product of $982.4 billion, the second highest in America after California. Texas is the only state in the U.S. to have three cities with populations exceeding one million: Houston, San Antonio, and Dallas; which are also among the 10 largest cities of the United States. They are larger than any other cities in the Southern United States. Austin, El Paso, and Fort Worth are in the top 25 largest U.S. cities.