Killeen is a city in Bell County, Texas, United States. As of the 2005 census estimate, the city had a total population of 100,233. It is a "principal city" of the Killeen-Temple-Fort Hood metropolitan area. Killeen is directly adjacent to the main cantonment of Fort Hood, and as such its economy is heavily dependent on the post and the soldiers (and their families) stationed there. According to the United States Census Bureau, the city has a total area of 91.7 km² (35.4 mi²). 91.6 km² (35.3 mi²) of it is land and 0.1 km² (0.1 mi²) of it (0.14%) is water.

As of the census of 2000, there were 86,911 people, 32,447 households, and 22,972 families residing in the city. The population density was 949.3/km² (2,458.9/mi²). There were 35,343 housing units at an average density of 386.0/km² (999.9/mi²). The racial makeup of the city was 45.78% White, 33.49% Black, 0.78% Native American, 4.33% Asian, 0.91% Pacific Islander, 8.99% from other races, and 5.72% from two or more races. Hispanic or Latino of any race were 17.80% of the population.