The Montreal River has an inverted check mark shape, first flowing 70 kilometres (43 mi) north east, then 150 kilometres (93 mi) south east to its mouth.
It begins at Smoothwater Lake in Lady Evelyn-Smoothwater Provincial Park.
Ishpatina Ridge, the highest point in Ontario, lies in the Montreal River drainage basin just south of Smoothwater Lake, and separates the headwaters of the Montreal River proper, to the northwest, and the headwaters of the tributary Lady Evelyn River, which joins far downstream, to the southeast.

The river heads north, takes in several tributaries and reaches Inlet Bay on Gowganda Lake and the community of Gowganda.
The river exits the lake at Outlet Bay, passes under Ontario Highway 560 and continues northeast.
It reaches The Forks at Matachewan and takes in the major left tributary West Montreal River.
 It continues northeast briefly to Fox Rapids, then turns southeast, passes under Ontario Highway 65, takes in the right tributary Sydney Creek and left tributary Council Creek and reaches the Ontario Power Generation (OPG) Indian Chute Generating Station and dam at Indian Chute Falls.
The river continues southeast to the community of Elk Lake, takes in the right tributary Makobe River and again passes under both Highway 65 and Highway 560.
The river continues southeast, passes through the Mountain Chutes, takes in the major right tributary Lady Evelyn River at the community of Mowat Landing, passes into Bay Lake and reaches the town of Latchford.
The river is paralleled by Highway 65 for the stretch Matachewan to Latchford.

The river heads over the Latchford Dam and under the Sgt.
Aubrey Cosens VC Memorial Bridge carrying Ontario Highway 11, attains OPG Hound Chute Generating Station and dam and further downstream Canadian Hydro Developers' Ragged Chute Generating Station and dam.
The river flows over Fountain Falls and the Paugan Rapids, and enters the reservoir of the OPG Lower Notch Generating Station and dam.
It then passes through the generating station to reach its mouth at Lake Timiskaming.
The Montreal River has an inverted check mark shape, first flowing 70 kilometres (43 mi) north east, then 150 kilometres (93 mi) south east to its mouth. It begins at Smoothwater Lake in Lady Evelyn-Smoothwater Provincial Park. Ishpatina Ridge, the highest point in Ontario, lies in the Montreal River drainage basin just south of Smoothwater Lake, and separates the headwaters of the Montreal River proper, to the northwest, and the headwaters of the tributary Lady Evelyn River, which joins far downstream, to the southeast.
The river heads north, takes in several tributaries and reaches Inlet Bay on Gowganda Lake and the community of Gowganda. The river exits the lake at Outlet Bay, passes under Ontario Highway 560 and continues northeast. It reaches The Forks at Matachewan and takes in the major left tributary West Montreal River.  It continues northeast briefly to Fox Rapids, then turns southeast, passes under Ontario Highway 65, takes in the right tributary Sydney Creek and left tributary Council Creek and reaches the Ontario Power Generation (OPG) Indian Chute Generating Station and dam at Indian Chute Falls. The river continues southeast to the community of Elk Lake, takes in the right tributary Makobe River and again passes under both Highway 65 and Highway 560. The river continues southeast, passes through the Mountain Chutes, takes in the major right tributary Lady Evelyn River at the community of Mowat Landing, passes into Bay Lake and reaches the town of Latchford. The river is paralleled by Highway 65 for the stretch Matachewan to Latchford.
The river heads over the Latchford Dam and under the Sgt. Aubrey Cosens VC Memorial Bridge carrying Ontario Highway 11, attains OPG Hound Chute Generating Station and dam and further downstream Canadian Hydro Developers' Ragged Chute Generating Station and dam. The river flows over Fountain Falls and the Paugan Rapids, and enters the reservoir of the OPG Lower Notch Generating Station and dam. It then passes through the generating station to reach its mouth at Lake Timiskaming.
Montreal River (Timiskaming District)