Crystal Lake, FL has a population of 6,413 and is the 5,517th largest city in the United States. The population density is 2,512 per sq mi which is 755% higher than the Florida average and 2672% higher than the national average. The median age in Crystal Lake is 31 which is approximately 26% lower than the Florida average of 42. In Crystal Lake, 32% of the population over 15 years of age are married, 76% speak English and 20% speak Spanish. 48% of Crystal Lake residents were born in Florida, 39% were born out of state, 6% were born outside of the United States and 7% were foreign born.