East Fork South Fork McKenzie River

The East Fork South Fork McKenzie River is a tributary of the South Fork McKenzie River in Lane County in the U.S. state of Oregon. It begins in and passes through part of the Willamette National Forest of the Cascade Range. Flowing generally northwest along the base of Sawtooth Ridge, it empties into Cougar Reservoir on the South Fork McKenzie River, about 5 mi upstream of that stream's mouth on the McKenzie River.

The East Fork, which has no named tributaries, runs along the north edge of the Three Sisters Wilderness. East Fork Trail 3308 follows the stream for much of its length, crossing it twice on footbridges.