The Menan Buttes are two prominent volcanic tuff cones on Idaho’s Snake River Plain near Menan, Rigby, Rexburg, and Idaho Falls. Rising about 800 feet above the plain, they are part of the six-cone Menan Complex formed in the late Pleistocene about 10,000 years ago by explosive interaction between basaltic magma and water. Steam shattered the magma into glassy fragments and built steep tuff cones, some layers still showing bomb sags from falling volcanic debris. Among the world’s largest volcanic tuff cones, the buttes preserve an unusual record of explosive basaltic volcanism. North Menan Butte is slightly larger and publicly protected, while South Menan Butte is privately owned.