Austin is the capital city of the U.S. state of Texas. It is the seat and most populous city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 26th-largest metropolitan area in the United States, the 12th-most populous city in the United States, the fourth-most populous city in the state after Houston, San Antonio, and Dallas, and the second-most populous state capital city after Phoenix, the capital of Arizona. It has been one of the fastest growing large cities in the United States since 2010. Downtown Austin and Downtown San Antonio are approximately 80 miles (129 km) apart, and both fall along the I-35 corridor. This combined metropolitan region of San Antonio–Austin has approximately 5 million people. Austin is the southernmost state capital in the contiguous United States and is considered a Gamma + level global city as categorized by the Globalization and World Cities Research Network.

As of the 2020 census, Austin had a population of 961,855. The city is the cultural and economic center of the Austin–Round Rock metropolitan statistical area, which had an estimated population of 2,473,275 as of July 1, 2023. Located in Central Texas within the greater Texas Hill Country, it is home to numerous lakes, rivers, and waterways, including Lady Bird Lake and Lake Travis on the Colorado River, Barton Springs, McKinney Falls, and Lake Walter E. Long.

Residents of Austin are known as Austinites. They include a diverse mix of government employees, college students, musicians, high-tech workers, and blue-collar workers. The city’s official slogan promotes Austin as “The Live Music Capital of the World”, a reference to the city’s many musicians and live music venues, as well as the long-running PBS TV concert series Austin City Limits. Austin is the site of South by Southwest (SXSW), an annual conglomeration of parallel film, interactive media, and music festivals. The city also adopted “Silicon Hills” as a nickname in the 1990s due to a rapid influx of technology and development companies. In recent years, some Austinites have adopted the unofficial slogan “Keep Austin Weird”, which refers to the desire to protect small, unique, and local businesses from being overrun by large corporations. Since the late 19th century, Austin has also been known as the “City of the Violet Crown”, because of the colorful glow of light across the hills just after sunset.