Crystal Lake, CT has a population of 2,068 and is the 10,821st largest city in the United States. The population density is 264 per sq mi which is 59% lower than the Connecticut average and 192% higher than the national average. The median age in Crystal Lake is 43 which is approximately 5% higher than the Connecticut average of 41. In Crystal Lake, 69% of the population over 15 years of age are married, 94% speak English and 1% speak Spanish. 71% of Crystal Lake residents were born in Connecticut, 25% were born out of state, 1% were born outside of the United States and 3% were foreign born.