Prominent east side buttress just across from the trestle.
From the bottom of the upper approach, hike right and cross the river at the trestle. Hike up and left to the cliff.
Browse More Classics in Underground Cliff
Mountain Project's determination of some of the classic, most popular, highest rated routes for Underground Cliff:
Get Over It 5.10c Sport, 1 pitch, 50 feet
Featured Route For Underground Cliff