Craters of the Moon National Monument, Idaho
Craters of the Moon National Monument and Preserve, a striking testament to the raw power of volcanic forces, stretches across a vast expanse of southern Idaho. Situated on the Snake River Plain, this protected area presents a surreal landscape, a dramatic tableau of hardened lava flows punctuated by cinder cones and resilient sagebrush. Spanning approximately 715,000 acres, the monument offers an unparalleled glimpse into a geological wonderland, showcasing volcanic craters, intricate lava tubes, profound fissures, and extensive lava fields. The sheer scale and unique features of Craters of the Moon National Monument, Idaho, make it a destination unlike any other.
The story of this extraordinary landscape is etched in stone, revealing a relatively recent chapter in the Earth’s fiery history. The dominant rock formations are the product of volcanic eruptions, specifically "fissure eruptions," which occurred along cracks in the Earth’s crust. These eruptions began roughly 15,000 years ago, shaping the terrain we see today. While volcanic activity has been a long-term geological process in the Snake River Plain, the features of Craters of the Moon National Monument, Idaho, are attributable to the most recent period of volcanism in the region, with the latest activity dated back approximately 2,100 years.
Unlike the stereotypical image of a large, cone-shaped volcano with a summit crater, the volcanic fissures here offer a different perspective on volcanic activity. Each cinder cone represents a small volcano, characterized by eruptions of highly fluid basaltic lava. This type of lava allowed gases to escape relatively easily. The absence of significant gas pressure resulted in mild eruptions that, nevertheless, produced extensive lava flows, contributing to the vast and intricate landscape of Craters of the Moon National Monument, Idaho.
The National Monument encompasses the Great Rift, a geological feature of immense significance. This rift contains a remarkable concentration of volcanic landforms and structures, extending along a zone of fractures and eruptions that stretches for more than 50 miles. Within this zone lies a composite field composed of approximately 60 distinct lava flows and 25 cones. This represents the most significant collection of this lava flow type found within the lower 48 states, underscoring the exceptional geological value of Craters of the Moon National Monument, Idaho.
Despite the seemingly inhospitable environment of hardened lava, life has found a way to persist and even thrive in Craters of the Moon National Monument, Idaho. As the molten lava fields cooled over time, plants and animals gradually began to occupy the area. While some species, such as the big horned sheep and grizzly bear, disappeared from the region nearly a century ago, many other species continue to flourish. The rugged terrain and scarcity of water have acted as natural barriers, discouraging extensive human development and preserving the landscape from the encroachment of roads, buildings, farms, and power lines that characterize much of the surrounding Snake River Plain.
Although the harsh conditions prevented permanent settlements within the lava flows, evidence indicates that the Northern Shoshone people utilized the area for hunting and gathering. Archaeological discoveries within the monument have unearthed numerous artifacts, temporary shelters, and hunting blinds. These findings suggest that the Shoshone people frequented the area to hunt and gather tachylite, a dense form of basalt, which they used to craft arrow points. The presence of these artifacts provides a glimpse into the historical connection between humans and this seemingly desolate landscape.
In late spring, a subtle yet captivating transformation occurs across the cinder slopes of the monument. Tiny wildflowers emerge, adorning the landscape with delicate splashes of color. The seemingly deliberate spacing of these flowers, appearing almost as if they were planted in neat rows, is a result of the harsh environmental conditions. Plants in this area must compete for a limited supply of water. Consequently, they cannot grow too closely together and survive. Instead, they space themselves naturally, optimizing their access to the limited resources available. This exemplifies the resilience and adaptability of life in Craters of the Moon National Monument, Idaho.
The unique natural features of Craters of the Moon are diverse and captivating. Among these are the lava tube caves, such as the Indian Tunnel, which stretches for an impressive 800 feet and is accessible to explorers. Big Cinder Butte, a towering basaltic cinder cone, rises to a height of 700 feet, making it one of the largest of its kind in the world. The Blue and Green Dragon flows, named for their striking and unusual lava colors, add to the visual spectacle. In addition to the lava formations, the monument also encompasses large areas of sagebrush steppe and numerous kipukas. These kipukas are isolated islands of remnant vegetation, protected by the surrounding lava flows. They act as small, virtually undisturbed havens for native plants and animals, providing valuable insights into the pre-volcanic ecosystem.
It is important to note that Craters of the Moon National Monument, Idaho, is considered a dormant rather than an extinct volcanic area. The volcanoes here are not dead but rather sleeping. While there have been no recent indications of impending eruptions, such as earthquakes, the opening of steam vents, or ground swelling, geologists believe that the area will likely become active again within the next 1,000 years. This potential for future volcanic activity underscores the dynamic and ever-changing nature of this geological wonder.
Today, visitors to Craters of the Moon National Monument, Idaho, can explore this isolated and awe-inspiring landscape through a variety of activities. Several hiking trails offer unique opportunities to encounter the diverse plants and animals that inhabit the various lava habitats. For those who prefer a less strenuous experience, a driving tour is available along the Seven-mile Loop Road. The Visitor’s Center provides valuable information and exhibits, enhancing understanding of the monument’s geological and ecological significance. A campground is also available during the summer months, allowing visitors to immerse themselves in the unique atmosphere of this volcanic landscape.
The visitor center is conveniently located approximately 18 miles southwest of Arco, Idaho, along Highway 20, and 50 miles northeast of Shoshone on Highway 26, making it easily accessible for travelers.
Contact Information:
Craters of the Moon National Monument & Preserve
P.O. Box 29
Arco, Idaho 83213
Visitor Information – 208-527-1300
Headquarters – 208-527-1300
Primary Source: National Park Service
Also See:
Idaho – The Gem State
Idaho Photo Galleries
National Parks, Monuments & Historic Sites
The Shoshone