Eagle Lake is the first, largest, and deepest lake of the Allagash Wilderness Waterway in the North Maine Woods. The lake covers the eastern side of Eagle Lake township. The southern end of the lake extends into Maine township 7, range 12, where it receives overflow from Indian Pond, and into Soper Mountain township where it receives overflow from Haymock Lake via Smith Brook. Other ponds in the Eagle Lake watershed include Woodman Pond via Woodman Brook, Pillsbury Pond and Little Pillsbury Pond via Smith Brook, Soper Pond and Upper Soper Pond via Soper Brook, and the Russell Ponds via Russell Brook. Eagle Lake originally received overflow from Chamberlain Lake, but Lock Dam has diverted most Chamberlain Lake overflow through Telos Cut to the Penobscot River since the 1850s.