The Sol Duc River (also spelled Soleduck) is a river in the U.S. state of Washington. About 78 miles (126 km) long, it flows west through the northwest part of the Olympic Peninsula, from the Olympic Mountains of Olympic National Park and Olympic National Forest, then through the broad Sol Duc Valley. Near the Pacific Ocean the Sol Duc River joins the Bogachiel River, forming the Quillayute River, which flows about 4 miles (6.4 km) to the Pacific Ocean at La Push.