Killeen is a city in the U.S. state of Texas, located in Bell County. According to the 2020 census, its population was 153,095, making it the 19th-most populous city in Texas and the largest of the three principal cities of Bell County. It is the principal city of the Killeen–Temple–Fort Cavazos Metropolitan Statistical Area. Killeen is 55 miles north of Austin, 125 miles southwest of Dallas, and 125 miles northeast of San Antonio.