Ennis Lake (Ennis Reservoir or Meadow Lake) is a silty shallow reservoir backed up by a rather small Montana Power dam on the Madison just below the lake. Because it’s so shallow, Ennis Lake gets very warm during the summer. The warm water makes for pleasant swimming but causes rampant algae growth and is generally rough on fish downstream. Because of the warm water, it’s best to fish the lower Madison (downstream of Ennis Lake) during the cooler weather of the spring and fall.
© W.C. McRae & Judy Jewell from Moon Montana, 7th Edition