Burlington, CO has a population of 4,139 and is the 7,293rd largest city in the United States. The population density is 1,983 per sq mi which is 3882% higher than the Colorado average and 2088% higher than the national average. The median age in Burlington is 39 which is approximately 7% higher than the Colorado average of 36. In Burlington, 68% of the population over 15 years of age are married, 85% speak English and 12% speak Spanish. 58% of Burlington residents were born in Colorado, 35% were born out of state, 0% were born outside of the United States and 7% were foreign born.