Historic Resource Study, Crater Lake National Park, Oregon, 1984
IX. Trails and Campgrounds of Crater Lake National Park
E. Summary of Park Trail System
5. Southwest Section of Park
a) Union Peak: 6,220 feet, reached by Union Peak loop motorway from Medford highway, three-fourths of a mile above Annie Spring. Motorway continued from Union Peak over Pumice Flat and rejoined main highway system near Cold Spring Campground.
b) Snow Crater: steep-walled depression filled with snow. No trail, but could be reached by following ridge south of Arant Point for about two miles.
c) Llao’s Hallway: spectacular chasm cut by tiny creek. Entered by trail down Whitehorse Creek starting from old campground on Medford highway, four miles below Annie Spring. 
The Pacific Crest National Scenic Trail crossed the west side of the park and wound southward twenty-five miles through the Sky Lakes Wilderness.