The South Fork Skokomish River originates near Sundown Pass in Olympic National Park, near the sources of the Wynoochee River and Graves Creek, a tributary of the Quinault River. The South Fork flows southeast out of the national park and between Capitol Peak, on the west, and Wonder Mountain on the east. After receiving Rule Creek from the west the South Fork turns more directly south and enters a broader valley. It receives Church Creek from the west, then turns to flow southeast and east through a widening river valley. A number of tributary streams join the South Fork, including Pine Creek and Cedar Creek, from the south, and Le Bar Creek, Brown Creek, and Harp Creek from the north. The South Fork Skokomish leaves the main Olympic Mountains and enters flatter terrain, but flows through gorges for several miles. After exiting the gorges the South Fork turns east and enters the broad Skokomish Valley where it joins with the North Fork to form the main stem Skokomish River.