Belle Isle, FL has a population of 6,542 and is the 5,436th largest city in the United States. The population density is 2,749 per sq mi which is 836% higher than the Florida average and 2934% higher than the national average. The median age in Belle Isle is 49 which is approximately 17% higher than the Florida average of 42. In Belle Isle, 64% of the population over 15 years of age are married, 81% speak English and 11% speak Spanish. 37% of Belle Isle residents were born in Florida, 48% were born out of state, 3% were born outside of the United States and 11% were foreign born.