The Tye River is a river in the U.S. state of Washington. It rises near Stevens Pass in the Cascade Mountains and flows west, joining the Foss River to form the South Fork Skykomish River. Its waters eventually empty into Puget Sound near Everett via the Skykomish River and Snohomish River. U.S. Route 2 follows the river's entire length. A BNSF Railway line follows most of the river except near the pass where the tracks use the Cascade Tunnel. Powerlines run by the Bonneville Power Administration (BPA) follow the Tye River west of Tunnel Creek.