Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city in the United States, the fourth-most-populous city in Texas, the second-most-populous state capital city, and the most populous state capital that is not also the most populous city in its state.
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 apart, and both fall along the Interstate 35 corridor. Some observers believe that the two regions may some day form a new "metroplex" similar to Dallas and Fort Worth. Austin is the southernmost state capital in the contiguous United States.