The South Fork Flathead River originates deep in Montana's Bob Marshall Wilderness, flowing north for approximately 60 miles before being impounded by Hungry Horse Dam and Reservoir. This pristine river system drains a remote watershed within the Rocky Mountains before joining the main stem of the Flathead River. The upper reaches offer a true wilderness experience, requiring either backpacking or horseback access.

The river's initial 60-mile stretch through the Bob Marshall Wilderness provides multi-day trip options for skilled paddlers, featuring Class III-IV whitewater. A highlight is the challenging 4-mile long wilderness gorge with Class IV-V rapids. Below the wilderness section, the Cedar Flats to Meadow Creek Gorge offers 20.5 miles of demanding Class IV-V whitewater. This section is more accessible via the West Side Road but still requires advanced skills to navigate the technical rapids and boulder gardens.

After exiting Hungry Horse Reservoir, the final 5-mile lower section flows from the dam to the confluence with the main Flathead. This Class II-III stretch features standing waves and rocky shoals, suitable for intermediate paddlers.

The South Fork's paddling season typically runs from mid-June through late August, with optimal flows in early summer. Anglers prize the river for its native westslope cutthroat trout and bull trout populations. Wildlife sightings may include elk, moose, and grizzly bears.

Key access points include the remote Bob Marshall Wilderness trailheads, Cedar Flats Access Site, and Hungry Horse Dam. The nearest towns are Hungry Horse and Columbia Falls.

As a federally designated Wild and Scenic River, the South Fork has strict regulations to preserve its pristine character. Group sizes are limited to 10 people in the wilderness section, and motorized boats are prohibited. Paddlers must be self-sufficient and prepared for a true backcountry experience in the upper reaches.

The South Fork Flathead offers a range of paddling experiences, from multi-day wilderness expeditions to more accessible day trips below the dam. Its remote nature, challenging whitewater, and unspoiled ecosystem make it one of Montana's premier paddling destinations for those seeking adventure in a pristine mountain environment.