Stevens Pass is a mountain pass through the Cascade Mountains located at the border of King County and Chelan County in Washington, United States. U.S. Route 2 travels over the pass, reaching a maximum elevation of 4,061 feet. The Pacific Crest Trail crosses the highway at Stevens Pass. The BNSF Railway's Cascade Tunnel lies 1,180 feet below the pass …Stevens Pass is a mountain pass through the Cascade Mountains located at the border of King County and Chelan County in Washington, United States. U.S. Route 2 travels over the pass, reaching a maximum elevation of 4,061 feet. The Pacific Crest Trail crosses the highway at Stevens Pass. The BNSF Railway's Cascade Tunnel lies 1,180 feet below the pass summit.