Delta, CO has a population of 8,813 and is the 4,339th largest city in the United States. The population density is 659 per sq mi which is 1224% higher than the Colorado average and 627% higher than the national average. The median age in Delta is 43 which is approximately 18% higher than the Colorado average of 36. In Delta, 58% of the population over 15 years of age are married, 84% speak English and 13% speak Spanish. 54% of Delta residents were born in Colorado, 40% were born out of state, 1% were born outside of the United States and 5% were foreign born.