Holly Hills, CO has a population of 2,684 and is the 9,400th largest city in the United States. The population density is 4,575 per sq mi which is 9089% higher than the Colorado average and 4950% higher than the national average. The median age in Holly Hills is 46 which is approximately 26% higher than the Colorado average of 36. In Holly Hills, 56% of the population over 15 years of age are married, 92% speak English and 7% speak Spanish. 39% of Holly Hills residents were born in Colorado, 56% were born out of state, 1% were born outside of the United States and 4% were foreign born.