Harker Heights, TX has a population of 28,716 and is the 1,491st largest city in the United States. The population density is 1,835 per sq mi which is 1524% higher than the Texas average and 1926% higher than the national average. The median age in Harker Heights is 32 which is approximately 5% lower than the Texas average of 34. In Harker Heights, 58% of the population over 15 years of age are married, 84% speak English and 8% speak Spanish. 35% of Harker Heights residents were born in Texas, 48% were born out of state, 7% were born outside of the United States and 10% were foreign born.