Long Lake is a large and deep lake in Aroostook County. It is part of the Fish River Chain of Lakes. The lake covers more than 5,000 acres and has a maximum depth of 163 feet. Long Lake is a popular destination for fishing, boating, and ice fishing in winter. The lake also has a unique feature: Pelletier Island, which is connected to the mainland by a causeway and has a potato field in the center.