Bureau of Land Management, Idaho.
The Gooding City of Rocks and the Little City of Rocks have unique rock formations rising from the desert floor. The Bennett Hills, located on the north edge of the Snake River Plain, are composed of welded volcanic tufts formed when intense volcanic eruptions in the region produced dense clouds of ash which fused together on the ground over time. If you do visit, use Leave No Trace hiking techniques.
Bennett Hills northwest of Gooding