From the trailhead along the west side of Yerba Buena Gorge
Lower Falls and its box canyon in a previous posting. Currently, there is no route known to expat hikers which leads from the base of the Lower Falls up to the base of the Upper Falls. The higher cascades can only be viewed from above. The Upper Falls canyon has tantalized us for years but entering it will require some serious technical rock climbing and rope work. It is not clear how, once in, one can then get out again.
A visit to the Upper Falls