Berlin Lake spans three counties. The eastern portion is in Stark County, the middle portion is in Portage County, and the western portion is in Mahoning County. See the map for the county line boundaries. 

Berlin Lake lies in the northeastern part of Ohio at the junction of Stark, Portage, and Mahoning counties. The lake is located on and is accessible from US-224 and OH-14 and OH-225. The U.S. Army Corps of Engineers constructed Berlin Lake in 1942 on the Mahoning River. The Congressionally authorized purposes were flood control, low flow augmentation, water quality control, and water supply. Berlin Lake has a mean depth of 23 feet with a maximum depth of 55 feet. Annual water level fluctuations can be as much as 20 feet. Mud, sand, and gravel make up most of the bottom composition. Rock ledges can be seen along the original river channel at low pool level.

Restroom facilities can be found at the headquarters building, the picnic area by the dam, and the Circle Restaurant in Deerfield.