Little Bitterroot River

The mountainous or hill country, reaches from the headwaters above U.S. 2 to north of Lone Pine. The river is surrounded by hills rather than mountains. The hills and mountains on the east side of the valley are nearly treeless, but those on the west side apparently receive more rain and snow, for they support a forest of large trees. The sides of the mountains are marked with horizontal lines that show the levels at which the water stood when Lake Missoula extended over this region.[2] The Little Bitterroot begins at pass above Marion on U.S. 2 where Forest Road (FR) 5344 and FR 538 or Griffin Creek Road. From this pass at 5,217 feet (1,590 m) above sea level (asl), the basin collects into Little Bitterroot Lake, 3,907 feet (1,191 m) asl. The south end of the lake drains into the Little Bitterroot River, flowing southward. For a few miles, the river shares its valley with U.S. 2. Here, Sickler Creek joins the Little Bitterroot, draining the basin of Lake Rogers to the east. Highway 2 continues west over a shallow pass into the McGregor Lake valley and the Little Bitterroot continues south, entering a narrow canyon and Hidden Lakes. Before reaching Hidden Lake, the river drops over a 2 miles (3.2 km) rapidly losing 117 feet (36 m) in elevation, reaching the lake which stands at 2,627 feet (801 m) asl. Through the Hidden Lake area, the canyons are flat bottom, evidence of glacial ice scouring this area. As the canyon opens into a wide flat bottom valley, Tamarack Creek enters from the west, just before reaching Hubbart Reservoir.