Killeen is a city in Bell County, Texas, United States. 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 Hood Metropolitan Statistical Area. Killeen is 55 miles (89 km) north of Austin, 125 miles (201 km) southwest of Dallas, and 125 miles (201 km) northeast of San Antonio.