South Fork Breitenbush River

The South Fork Breitenbush River is a 10 mi tributary of the Breitenbush River in the U.S. state of Oregon. The river flows generally northwest from Russell Lake in the Mount Jefferson Wilderness of the Cascade Range to near Breitenbush Hot Springs, where it merges with the North Fork Breitenbush River to form the main stem.

The South Fork receives Lake Creek and Roaring Creek, both from the right, as it descends through the wilderness and the Willamette National Forest. From the confluence of its forks, the main stem Breitenbush River flows about 11 mi further to its confluence with the North Santiam River in Detroit Lake.

Recreation
The Pacific Crest Trail crosses the South Fork near Russell Lake. South Breitenbush Trail, which parallels the river for about 6 mi in its upper reaches, offers opportunities for hiking and backpacking at elevations ranging from 3050 to 5850 ft above sea level.

South Breitenbush Gorge Trail, along the river closer to its confluence with the main stem, passes through older Douglas-fir and western hemlock forest. This trail, ranging in elevation from 2300 to 2800 ft, is 2.5 mi long. A side trail leads to a narrow canyon, about 300 ft long, where the river flows between walls of basalt.