Crystal Lake is a census-designated place (CDP) in Polk County, Florida, United States.

The town is located at 28.03525 N, 81.90847 W. As of the census[4] of 2000, there were 5,341 people, 2,151 households, and 1,383 families residing in the CDP.

The racial makeup of the CDP was 80.94% White, 13.63% African American, 0.75% Native American, 0.88% Asian, 0.02% Pacific Islander, 2.45% from other races, and 1.33% from two or more races.

There were 2,151 households, out of which 30.0% had children under the age of 18 living with them, 42.5% were married couples living together, 16.2% had a female householder with no husband present, and 35.7% were non-families.

25.6% of all households were made up of individuals, and 8.6% had someone living alone who was 65 years of age or older.