Forest Lake is an unincorporated community and census-designated place (CDP) in Ela Township of Lake County, Illinois, United States. It is about northwest of downtown Chicago. Per the 2020 census, the population was 1,784. The community was founded in 1935 as a vacation community for Chicago residents.
Geography
Forest Lake is located in southwestern Lake County. It is bordered to the north, west, and south by Hawthorn Woods, and to the east and south by Kildeer. The village of Lake Zurich boundary comes within of the southwest corner of the CDP.
According to the 2021 census gazetteer files, Forest Lake has a total area of , of which (or 85.16%) is land and (or 14.84%) is water, consisting of the community's namesake water body.