Castle Creek (Washington)

Castle Creek is a tributary of the North Fork Toutle River on the flank of Mount St. Helens in Washington state. It rises about two miles (three kilometers) northwest of the crater rim (46.2169°N, -122.23934°W) and flows generally to the northwest. The outflow of Castle Lake joins the creek at the lake's north end (46.258°N, -122.272°W) after traveling a few hundred meters on the South Fork Castle Creek. It joins the North Fork Toutle River at 46.28302°N, -122.29359°W, elevation 2,200 feet.

Castle Lake was created by an avalanche subsequent to the May 18, 1980 eruption of Mount St. Helens which blocked South Fork Castle Creek. Pre-1980 maps show this area as "Castle Creek Marsh".