Forest Lake Maine lies at the juncture of the towns of Cumberland, Gray, and Windham in Cumberland County, Maine. The lake serves as the headwaters to the Piscataqua River, which then flows into the Presumpscot River and Casco Bay. Formerly also known as Goose Pond, the lake has a surface area of 211 acres, with over 4 miles of shoreline, most of which is privately owned. The average depth is 12′ with a maximum depth recorded at 38′. As of 2017, 179 properties lie claim to lake frontage, with 96 additional properties adjacent to lakefront lands and 119 properties in the surrounding watershed. The entire watershed area encompasses just under 400 properties and covers about 3.3 square miles (2,174 acres), a small portion of which extends into Falmouth, Maine.