Jagged peaks seen from the Hoh River Trail. The Hoh River trail in Olympic National Park starts in the mossy and lush Hoh Rain Forest. From there you climb over 5,000 ft. in elevation along towering trees and rock to overlook the windswept Blue Glacier on Mt. Olympus. Tracing your steps back to the Hoh River visitors center the hike covers over 36 miles of diverse climate and ecosystems ranging from temperate rain forest to alpine.