Lake Mohegan and its surrounding open space comprise a total of 170.4 acres off Morehouse Highway. The Conservation Commission administers the open space property with its many hiking trails but the popular swimming area is managed by the Parks and Recreation Commission.

During the summer months, the man made fresh water lake is open to swimmers in a designated area supervised by lifeguards. There are ropes at several depths, and young children aren't allowed beyond a certain point without an adult. The large beach is sandy and sunny. There's little natural shade, so beach umbrellas are a must.

In addition to the swimming, Lake Mohegan has a sprinkler park for children. Built and paid for by the volunteer organization Safe Parks and Recreation for Kids (SPARK), the fun zone is full of spouts, faucets and misters that will delight tiny toddlers and their older siblings too. The lake also has a playground, a snack bar, picnic shelter and restroom facilities. Fairfield Parks and Recreation holds swimming lessons in the calm lake waters for children beginning at age four.