The county's surface is covered by plains in the west and mountainous terrain in the east. The Cascade Range passes through the eastern part of the county and includes the highest point in Snohomish County: Glacier Peak, at above sea level. Most of the eastern part of the county is preserved by the Mount Baker National Forest and Snoqualmie National Forest, which are consolidated into the Mount Baker-Snoqualmie National Forest. The mountains provide a source for several major rivers in the east, including the Snohomish, Skykomish, Snoqualmie, and Stillaguamish, that in turn form major bodies of water to the west.