| East Fork South Fork McKenzie River | |
| Map Size: | 300 |
| Pushpin Map: | USA Oregon |
| Pushpin Map Size: | 300 |
| Pushpin Map Caption: | Location of the mouth of East Fork South Fork McKenzie River in Oregon |
| Subdivision Type1: | Country |
| Subdivision Name1: | United States |
| Subdivision Type2: | State |
| Subdivision Name2: | Oregon |
| Subdivision Type4: | County |
| Subdivision Name4: | Lane |
| Source1: | Cascade Range |
| Source1 Location: | Willamette National Forest |
| Source1 Coordinates: | 44.0667°N -122.0953°W[1] |
| Source1 Elevation: | 4592feet[2] |
| Mouth: | South Fork McKenzie River |
| Mouth Location: | Cougar Reservoir |
| Mouth Coordinates: | 44.1153°N -122.2378°W |
| Mouth Elevation: | 1686feet |
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 5miles upstream of that stream's mouth on the McKenzie River.[3]
The East Fork, which has no named tributaries,[3] 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.[4]