Big Bear Mountain is a 5,641-foot summit located at the western edge of the North Cascades, in Snohomish County of Washington state. It is located midway between Three Fingers to its north, and Liberty Mountain to its south. Big Bear Mountain is situated in the Boulder River Wilderness on land administered by the Mount Baker-Snoqualmie National Fores…Big Bear Mountain is a 5,641-foot summit located at the western edge of the North Cascades, in Snohomish County of Washington state. It is located midway between Three Fingers to its north, and Liberty Mountain to its south. Big Bear Mountain is situated in the Boulder River Wilderness on land administered by the Mount Baker-Snoqualmie National Forest. Precipitation runoff from the mountain drains into tributaries of the Sauk and Stillaguamish Rivers.