The White River is a white, glacial river in the U.S. state of Washington. It flows about 75 miles (121 km) from its source, the Emmons Glacier on Mount Rainier, to join the Puyallup River at Sumner. It defines part of the boundary between King and Pierce counties.A second White River has its source in Glacier Peak Wilderness and flows southeast to Lake Wenatchee.CourseThe source of the White River is the Emmons Glacier on the northeast side of Mount Rainier. The river flows from ice caves at the toe of the glacier. Its upper reach is contained within Mount Rainier National Park. Shortly after emerging from the Emmons Glacier, the White River flows generally east, by the White River Campground, then the White River Ranger Station, after which it turns north. The river is paralleled by much of its upper course by State Route 410, called the Mather Memorial Parkway in the national park. After several miles the river exits Mount Rainier National Park and enters Mount Baker-Snoqualmie National Forest.
