Landmarks of Idaho

An unusually large number of significant points of interest can be found in Idaho. They are important aged landmarks.

Outstanding examples of U.S. natural history are highlighted and conserved under the National Natural Landmarks Program, administered by the Interior Department’s National Parks Service. It’s a national program that identifies and recognizes the best instances of biological or geological features on public and/or private lands.

National Natural Landmarks (NNL’s) are designated by the Secretary of the Interior. Less than 600 sites have been chosen in the United States to date, with eleven landmarks from throughout Idaho having been selected.


< Big Springs
East of U.S. Route 20 at Macks Inn. The spring is the source of the South Fork of the Henrys Fork River. The only first-magnitude spring in the country issuing from rhyolitic lava flows. Outpour is a full-blown river within 100 feet of the springs.

Big Southern Butte >
West of Atomic City and Cerro Grande off U.S. Route 26. A 300,000-year-old butte towering 2,500 feet over the eastern Snake River Plain. This Idaho landmark was once a geographical marker for wagon trains. Illustrates the scope of Quanternary volcanism in the western U.S.

< Crater Rings
Two symmetrical pit craters side-by-side, one of the few examples of this type of crater in the U.S. The pit craters, which were lava conduits, were formed by explosions and then a collapse. Northwest of Mountain Home off Interstate Route 84.

City of Rocks National Reserve>
15 miles SW of Elba, off State Route 77. Huge display of monolithic landforms created by exfoliation processes and weathering. Some of the oldest rock formations in the U.S. Was important landmark on the California Trail. See my article "Visit Idaho's Famous City of Rocks National Reserve" for more information.

< Great Rift System
Nearly 170,000 acres located 20 miles west of Aberdeen off State Route 39. Unusual geologically historic record of crustal drifting and basaltic volcanism. The site illustrates primary vegetation succession on a young lava flow. Outstanding Idaho landmark has few counterparts in the world.

Hagerman Fauna Sites >
Southwest of Hagerman off U.S. Route 30. The richest deposits of Upper Pliocene age terrestrial fossils, including Equus simplicidens (the horse), the site’s most famous. Some fossils here are 3.5 million years old. Located within the Hagerman Fossil Beds National Monument.

< Hell’s Half Acre Lava Field
180 square-mile lava field, 10 miles north of Blackfoot off Interstate Route 15. Young, fully exposed lava flow. An outstanding example of pioneer vegetations (trees, mosses and lichens) establishing themselves on a lava flow. Flow estimated at 28,000 years old.

Hobo Cedar Grove Botanical Area >
A 240-acre old-growth western red cedar forest, with a carpet of lady fern and Oregon boxwood. Trees up to 8-foot in diameter. One-half mile, self-guided nature loop trail, ideal for handicapped or elderly. Located 11 miles northeast of Clarkia off State Route 3.

< Menan Buttes
Two large buttes of glassy basalt lava. These glass tuff cones are only found in a few places in the world. Largest cone rises 800 feet. Cones elongated by prevailing winds. Both have craters one-half mile long and 300 feet deep. Located west of Rexburg off State Route 33.

Niagara Springs >
Off Interstate Route 84 southwest of Jerome. A little developed large springs spewing into the Snake River from the Snake River Plains aquifer system. An outstanding illustration of the enormous volume of water supplied by this huge aquifer. Road into canyon is narrow and steep.

< Sheep’s Rock
In the Payette National Forest, 13 miles north of Cuprum on Sheep Rock Road. Provides excellent view of horizontally layered lavas. Several types of metamorphic basalt, andesite, sandstone and conglomerate are visable here. Spectacular panoramic views. Overlooks Hell’s Canyon.