Name Image Date Location County Ownership Description Big Southern Butte 1976 Atomic City 43°24′05″N 113°01′26″W / 43.401389°N 113.023889°W /43.401389; -113.023889 (Big Southern Butte ) Butte federal (Bureau of Land Management ) A 2,500 ftRhyolitic dome that rises over the EasternSnake River Plain . It illustrates the scope and dimensions ofQuaternary volcanism in the western United States. Big Springs 1980 Island Park 44°30′01″N 111°15′19″W / 44.500278°N 111.255278°W /44.500278; -111.255278 (Big Springs ) Fremont federal (Caribou-Targhee National Forest ) The only first-magnitude spring in the country that issues forth fromrhyolitic lava flows. Cassia Silent City of Rocks 1974 Malta 42°04′34″N 113°42′06″W / 42.076026°N 113.701676°W /42.076026; -113.701676 (City of Rocks ) Cassia federal (City of Rocks National Reserve ) Monolithic landforms created by exfoliation processes on exposed massive graniteplutons . Crater Rings 1980 Mountain Home 43°11′27″N 115°51′35″W / 43.1907°N 115.8597°W /43.1907; -115.8597 (Crater Rings ) Elmore federal (Morley Nelson Snake River Birds of Prey National Conservation Area ) Two adjacent and symmetricalpit craters that are among the few examples of this type of crater in the continental United States. Great Rift of Idaho 1968 Craters of the Moon National Monument and Preserve 43°27′42″N 113°33′46″W / 43.46167°N 113.56278°W /43.46167; -113.56278 (Great Rift ) Blaine ,Minidoka ,Power federal (Craters of the Moon National Monument and Preserve) A tensional fracture in the Earth's crust. Hagerman Fauna Sites 1975 Hagerman Fossil Beds National Monument 42°47′26″N 114°56′41″W / 42.7906°N 114.9448°W /42.7906; -114.9448 (Hagerman Fossil Beds ) Twin Falls federal (Hagerman Fossil Beds National Monument) Contains the world's richest deposits ofUpper Pliocene age terrestrial fossils. Hell's Half Acre Lava Field 1976 Blackfoot 43°30′N 112°27′W / 43.5°N 112.45°W /43.5; -112.45 (Hell's Half Acre Lava Field ) Bingham ,Bonneville federal (Bureau of Land Management) Fully exposedpahoehoe lava flow. Hobo Cedar Grove Botanical Area 1980 Shoshone 47°05′28″N 116°07′37″W / 47.0911°N 116.127°W /47.0911; -116.127 (Hobo Grove ) Shoshone federal (St. Joe National Forest ) An outstanding example of pristinewestern red cedar forest. Menan Buttes 1980 Menan 43°36′N 111°30′W / 43.6°N 111.5°W /43.6; -111.5 (Menan Buttes ) Jefferson ,Madison federal (Bureau of Land Management) Contains outstanding examples of glasstuff cones, which are found in only a few places in the world. Niagara Springs 1980 Hagerman 42°51′28″N 114°52′35″W / 42.85778°N 114.87639°W /42.85778; -114.87639 (Niagara Springs ) Gooding private Least developed of the large springs discharging into theSnake River from the Snake River plain aquifer system. Sheep Rock 1976 Council 45°11′30″N 116°40′17″W / 45.191651°N 116.67132°W /45.191651; -116.67132 (Sheep Rock ) Adams federal (Payette National Forest ) Horizontally layered lavas that represent successive flows on theColumbia River Basalt Plateau . 
