6,000 years ago glaciers cut this canyon out, now these two falls run over the glacier cut cliff. Lava from cinder cones near North Sister then filled the valley floor. As the water falls over the cliff and down into the porous lava it sinks back underground so it appears as if the water just disappears, without an outlet.
From McKenzie River Ranger Station, drive east on Highway 126 about 2 miles to junction with Highway 242. Drive about 10 miles up Highway 242 to the Proxy Falls Trailhead.