Key Colony Beach, FL has a population of 696 and is the 17,509th largest city in the United States. The population density is 1,581 per sq mi which is 438% higher than the Florida average and 1645% higher than the national average. The median age in Key Colony Beach is 65 which is approximately 56% higher than the Florida average of 42. In Key Colony Beach, 82% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 8% of Key Colony Beach residents were born in Florida, 83% were born out of state, 1% were born outside of the United States and 8% were foreign born.