Craters of the Moon National Monument is one of the best places in the world to see the awesome effects of volcanism. For 15,000 years, lava eruptions have created a landscape that has forced animals and plants to adapt and people to endure or detour and to ponder. Established in 1924, the monument celebrated its 75th birthday in 1999. The Craters of the Moon Lava Field covers 618 square miles and is the largest young basaltic lava field in the conterminous United States. The monument preserves 83 square miles of it for the enjoyment of present and future generations. The park contains more than 20 volcanic cones including outstanding examples of spatter cones. There are 60 different lava flows on the surface and they range in age from 15,000 to just 2,000 years old.
The monument is part of the Snake River Plain, a volcanic terrain that spans all of southern Idaho. In places, this plain is 60 miles wide and drilling into it has shown its lava deposits to be over 10,000 feet deep in some locations. Eruptions that took place 2,000 years ago at Craters of the Moon National Monument are the most recent volcanic activity to take place anywhere in this immense geographic area.
Today at Craters of the Moon, you can explore such features as cinder cones, spatter cones, lava tubes and several types of lava flows. You can also have the unique opportunity to encounter the plants and animals associated with the varied lava habitats, enjoy hiking on a variety of trails, or enjoy the solitude and beauty of this incredible place.
Introduction
The Craters of the Moon National Monument is a geologic wonder cast in a wild and remote landscape. Its central focus is the Great Rift, a 62 mile long crack in the earth’s crust. The Great Rift is the source of a remarkably preserved volcanic landscape with an array of exceptional features. Craters, cinder coves, lava tubes, deep cracks and vast lava fields form a strangely beautiful volcanic sea on central Idaho’s Snake River Plain. Volcanic eruptions first occurred at Craters of the Moon about 15,000 years ago. The most recent eruptions ended about 2,100 years ago and were likely witnessed by the Shoshone people. A Shoshone legend speaks of a serpent on a mountain who, angered by lightening, coiled around and squeezed the mountain until liquid rock flowed, fire shot from cracks and the mountain exploded.
The volcanic area now lies dormant, but its eight eruptive periods formed 60 lava flows which traveled as far as 45 miles from their vents. Some of the lava flowed around areas of higher ground, forming isolated islands of vegetation called “kipukas”. Today, these kipukas provide a window on the vegetation communities of the past. They contain some of the last pristine vegetation in the Snake River Plain, including 700-year-old juniper trees and relic stands of sagebrush and native bunchgrass.
The Craters of the Moon National Monument was established by President Coolidge on May 2, 1924. Since 1924, the monument has been expanded through five presidential proclamations issued in accordance with the Antiquities Act. The most recent and largest expansion of the monument occurred November 9, 2000 when President Clinton signed a Proclamation enlarging the monument 13-fold. The monument now contains 715,000 acres of federal land.
The expanded monument assures the protection of the entire Great Rift volcanic zone. It encompasses a remote area which includes the Kings Bowl lava field, Wapi lava field and the Bear Trap lava tube. The Bear Trap lava tube is an unusual, 15 mile-long cave system that contains well-preserved lava stalactites and curbs that mark the high level of flowing lava on the lava tube walls.
Nature & Science
Rocks from relatively recent volcanic eruptions dominate the landscape of Carters of the Moon National Monument and Preserve. Plants and animals began occupying the area while the once molten lava fields were still cooling. Some, like the big horned sheep and grizzly bear have been gone for almost 100 years. Most continue to thrive here. Difficult access due to rugged terrain and a lack of water discouraged people from altering the landscape with the roads, buildings, farms and powerlines which occupy much of the present day Snake River Plain. Craters of the Moon National Monument and Preserve encompass the entire Great Rift volcanic rift zone. It contains a huge concentration of volcanic landforms and structures along the more than 50 mile zone of fractures and eruptions. A composite field made up of about 60 lava flows and 25 cones, the Craters of the Moon Lava Field is the largest of its type in the lower 48 states. It is also the largest and most complex of the late Pleistocene and Holocene basaltic lava fields of the Eastern Snake River Plain. It has nearly every type of feature associated with basaltic systems and roads or trails offer convenient access to examples of most of them.
The Craters of the Moon Lava Field is the northernmost of the three lava fields found along the Great Rift, a system of crustal fractures that begins at the base of the Pioneer Mountains north of the Monument and extends for more than 50 miles to the southeast. The flows of the Craters of the Moon Lava Field have parent magma similar to that in the rest of the Snake River Plain, but exhibit a wide range of chemical compositions due to crustal contamination and crystal fractionation.
The Wapi Lava Field is the southernmost of these three fields. The Craters of the Moon Lava Field formed from magma that pushed up along the Great Rift. The magma that formed the Kings Bowl and Wapi Lava Fields also came up along the Great Rift, but originated in a different magma chamber. The Great Rift and other volcanic rifts on the Eastern Snake River Plain are predominantly parallel to, but not all are collinear with, basin and range faults north and south of the plain. The Craters of the Moon Lava Field was formed during eight major eruptive periods over the past 15,000 years. In contrast, most of the other lava fields on the Eastern Snake River Plain (including Kings Bowl and Wapi) represent single eruptions.
Unique natural features at Craters of the Moon include lava tubes caves such as Indian Tunnel, which is passable for 800 feet; Big Cinder Butte, at 700 feet, one of the largest purely basaltic cinder cones in the world; and the Blue and Green Dragon flows, which are named for their striking lava colors. The monument also contains large areas of sagebrush steppe as well as numerous kipukas. Kipukas are isolated islands of remnant vegetation protected by surrounding lava flows that act as small, virtually undisturbed havens for native plants and animals. Hundreds of small kipukas are scattered throughout the Craters of the Moon and Wapi lava fields.
Recreation
Biking
It took 15,000 years for the volcanic landscape at Craters of the Moon to evolve. It cannot be fully seen and appreciated from the window of an automobile. Slow your pace and you will notice details of this strange world which you might otherwise miss. Traveling by bicycle is a perfect way to explore the bizarre formations here.
Craters Loop Drive
The 7 mile road through the monument winds past cinder cones, lava flows and spatter cones. It provides access to trails to tree molds, caves and other points of interest. Most of the Loop Drive consists of gentle hills. However, there is a mile-long uphill grade from the beginning of the one-way loop to the Inferno Cone parking area. There is also a very steep, short downhill section just beyond the Spatter Cones. Bicycle racks are provided at all major parking areas. If you want to hike from other locations, you may lock your bicycle to some other object.
Bicycling is permitted on the Loop Drive and on Goodale’s Cutoff north of the highway. Bicycles are not permitted on hiking trails.
Goodale’s Cutoff
A dirt road north of US Highway 20/26/93 offers a more remote experience for those who want to get away from cars and people. It also allows you to experience a part of Craters of the Moon history.
Ride east from the visitor center on US Highway 20/26/93 for one half mile. Go around the locked gate on the north side of the highway and follow the dirt road along the base of Sunset Cone. Beyond the Group Campground, the main road continues west. A less-travelled track branches northeast and you may follow this route one half mile to the monument boundary.
If you choose instead to continue west past the group campground on the main road, watch for the spot 1 mile farther where the fainter Goodale’s Cutoff route heads west off of the main road. The road above this point is closed to visitors to protect the monument water supply, which comes from springs in this area. The stream corridors are also home to sensitive species of plants and animals, which could be disturbed by your presence. Please help us to protect these resources by respecting this closure.
The east & west boundaries of the monument are both designated by locked gates. Lands outside the monument may be under private ownership where permission is required prior to entry.
Restrictions on Goodale’s Cutoff:
- The main road north of Goodale’s Cutoff is closed to visitors.
- Overnight camping is not allowed.
- A free permit is required for bike travel. You may obtain one at the visitor center.
- For your safety, biking is not allowed during hunting season (October-November). Although hunting is not permitted in the monument, many people hunt just outside the boundary.
History of Goodale’s Cutoff
In the mid-1800’s, tens of thousands of emigrants passed through southern Idaho on their way to fertile farmland and gold fields to the west. The traffic peaked in 1864 when 40,000 people travelled the Oregon Trail about 100 miles south of here.
In 1862 an emigrant party asked guide Tim Goodale to lead them west from Fort Hall on an alternate route. They thereby hoped to reach the gold fields north of Boise more directly. Goodale led a group of 1,095 people, 338 wagons and 2,900 head of stock safely from Fort Hall to Boise. It took this enormous wagon train, the largest to travel any section of the Oregon Trail, over three hours to get into or out of camp.
The pioneers travelled north from Fort Hall toward Big Southern Butte, passed near the present-day town of Arco, wound through the northern part of Craters of the Moon, went southwest to Camas Prairie and ended at Fort Boise. This journey typically took two to three weeks. The road you will be riding on is one section of this historic trail.
Getting There
By Plane
Nearest airports are located in Hailey, Idaho (60 miles), Idaho Falls, Idaho (84 miles) and Twin Falls, Idaho (90 miles)
By Car
18 miles southwest of Arco, Idaho on Highway 20/26/93, 24 miles northeast of Carey, Idaho on Highway 20/26/93, 84 miles from Idaho Falls and 90 miles from Twin Falls.
Traveler Facts
Contact Information
Craters of the Moon National Monument
National Park Service
P. O. Box 29
Arco, ID 83213
Phone: 208-527-3257
Fax: 208-527-3073
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Craters of the Moon National Monument
Bureau of Land Management
Shoshone Field Office
P. O. Box 2B
Shoshone, ID 83352
Operating Hours & Seasons
The Craters of the Moon National Monument and Preserve remain open all year, although winter snows limit automobile access around the Loop Drive and on roads in the Preserve. The visitor center is open seven days a week throughout the year except for winter holidays. The visitor center contains a museum with exhibits explaining the natural and cultural history of the area.
A seven mile scenic drive starts just beyond the visitor center. This drive provides scenic views of lava flows and cinder cones and trail hiking opportunties ranging from a few hundreds yards to eight miles. A campground near the visitor center provides sites for campers.
Weather/Climate
The area around the Craters of the Moon National Monument is a high desert climate. The elevation at the visitor center is 5,900 feet. Temperatures increase and precipitation decreases as elevation drops in the southern reaches of the monument and preserve.
