Moosehead Lake is a deep, coldwater lake located in Piscataquis County in Northwestern Maine. It is the second-largest lake in New England, and the largest mountain lake in the eastern United States. Situated in the mostly undeveloped Longfellow Mountains, the lake is the source of the Kennebec River. Several rural Townships border the lake. Greenville is by far the largest town on the lake, with a small downtown area that has banks, shops, and restaurants. There are over 80 islands in the lake, the largest being Sugar Island and Deer Island to the west being the second largest.