It is the source of the Montreal River and is located between Highways 2 and 969.

[3] Montreal Lakes's catchment includes the northern slopes of the Waskesiu Hills[4] and the southern and eastern slopes of the Thunder Hills.

Also on the western shore is the Weyakwin River, which flows from Weyakwin Lake, and MacLennan River, which flows from the south side of the Thunder Hills.

Montreal River heads northward and flows into Lac la Ronge.

Fish commonly found in the lake include walleye, yellow perch, northern pike, lake trout, lake whitefish, cisco, burbot, white sucker, and longnose sucker.