Around the base of the mountain, there are a number of lakes, including the Lake of the Woods and Fourmile Lake. The Upper Klamath Lake, the largest body of freshwater in the state, sits to the east of Mount McLoughlin. The Summit Lake is a small lake on the northern slope of the volcano between the Rogue River and the Klamath Basin. The Big Butte Creek, a tributary of the Rogue River, drains the northwestern part of McLoughlin, while the Little Butte Creek is fed by the southern flanks.