Lake Jean is the 245-acre lake at the heart of Ricketts Glen State Park, on the plateau just east of Lake Rose. It is the centre of the park's developed area, with a swimming beach (open Memorial Day through Labor Day), boat rentals, and the main family campground.
Non-motorised boats and electric craft are allowed. The beach is sandy and the water clean and cold. In autumn, the surrounding maples and beeches turn brilliant red and orange, reflected in the lake — one of the best fall-colour spots in this part of Pennsylvania.