Upper Mesa Falls is a waterfall located on the Henrys Fork within the Caribou-Targhee National Forest. It is situated upstream from Lower Mesa Falls and is approximately 16 miles (26 kilometers) from Ashton, Idaho. The waterfall stands about 114 feet (35 meters) tall and spans roughly 200 feet (61 meters) in width.

Formation

Mesa Falls Tuff, the rock over which Upper Mesa Falls flows, was created 1.3 million years ago. Volcanic activity from the Henrys Fork caldera spread a thick layer of rock and ash across the region. Over time, this layer became compact and solid.

Between 200,000 and 600,000 years ago, the river carved a wide canyon. This canyon was later partially filled with basalt lava flows. The Henrys Fork of the Snake River then carved a path through the basalt, forming the inner canyon that exists today.