Crystal Lake is a city in Hancock County, Iowa, United States.

[4] According to the United States Census Bureau, the city has a total area of 0.26 square miles (0.67 km2), all land.

There were 134 housing units at an average density of 540.4 per square mile (208.6/km2).

There were 140 housing units at an average density of 538.5 per square mile (207.9/km2).

36.4% of all households were made up of individuals, and 13.2% had someone living alone who was 65 years of age or older.

There were 141 housing units at an average density of 553.4 per square mile (213.7/km2).

32.3% of all households were made up of individuals, and 14.2% had someone living alone who was 65 years of age or older.

About 20.3% of families and 19.1% of the population were below the poverty line, including 21.1% of those under the age of eighteen and 17.2% of those 65 or over.

Residents are part of the Forest City Community School District.