Good Sam RV Travel Guide & Campground Directory

Idaho’s Incredible Craters of the Moon

Charles Shugart Jr.









Important fact: the hotspot is not moving; the continental crust is.

Additionally, Craters of the Moon had numerous volcanoes and lava flows during more recent millennia. It is, in fact, the most extensive lava field in the lower 48 states, with 618 square miles. It's also one of the best and most easily accessible places to enjoy and learn about volcanoes and lava.

A major rift – a rupture in the earth's crust – runs right through Craters of the Moon and all the way to Yellowstone Park. There is evidence of lava activity along most of the rift.

Craters of the MoonAlthough annual precipitation in the monument is between 15 and 20 inches, lava rock is often quite porous and has many thousands of cracks. Thus, little moisture remains near enough to the surface to support much plant life except that which is highly adapted for desert regions. Sagebrush is perhaps the most common, but even then, individual plants tend to be scattered.

What does happen to the water? Most of it soaks quickly downward until reaching the slower–cooling and therefore non–porous rock. Then it seeps sideways and down slope – slowly – toward the Snake River, where it reappears as fresh water springs.

A bit of people history in the region:


As with all of North America, the earliest humans to inhabit the region of the lava beds were Native Americans, who first roamed the continent 12,000 years ago. In more recent years, the Northern Shoshone moved in. As hunter–gatherers, they were on the move much of the time, and therefore left little archeological evidence of their presence. Lava rock walls were made by these early people as protection from the strong, hot winds of summer, but no permanent structures were built. Winters were spent along the Snake River, where warmer temperatures and year–round water served their needs, as well as attracting many of the wildlife species they preyed upon. Among the large animals they hunted were elk, bighorn sheep and bison.

Craters of the MoonThe first white people other than the Lewis and Clark Expedition (which followed the more southerly Snake River) were trappers. But they also were interested in waterways because that was where the best fur–bearing animals were found. Specifically, they were after beavers, and thus avoided the arid ruggedness of what is now Craters of the Moon.

After the trappers came gold prospectors, and then the settlers who wanted to build ranches and raise cattle or food crops such as wheat. Lava fields held no valuable minerals for the prospectors, and nobody could raise crops or cattle on the jagged lava fields, so the land was largely ignored. It still is.

There were occasional government explorers also. Often they were surveying new land the United States had bought … the Louisiana Purchase. The concept of eminent domain stretched those boundaries quite a bit, and, because no other country was settling the west in any great numbers, well, the U.S. grabbed it all.

As history and western movies have taught us, nobody asked the Native Americans. The U.S. pushed them aside – or killed them – and simply took it. Being civilized has never been easy.

Craters of the Moon National Monument was established in 1924 by President Calvin Coolidge to "Preserve the unusual and weird volcanic formations. " It was incorrectly assumed by many to be similar to the surface of the moon, hence the name.

Craters of the Moon is volcanic. The moon's surface is not.

When the United States began exploring the moon, especially with the Apollo program, NASA discovered that its surface was not so much volcanic; but was instead peppered with many thousands of craters caused by impacting meteorites. Never–the–less, Apollo Astronauts trained at Craters of the Moon because the terrain was similar to that of the moon's surface.

Visiting this "Unusual and weird" place:


The national monument has a campground that is perfectly located for a one night stand. It's a basic national park kind of place, providing everything RVers need except hookups. With only 52 sites and no reservations, morning arrivals are suggested. That way you can get settled in, disconnect, take a seven–mile loop road through the monument, and enjoy a relaxed evening in camp. There is a Visitor Center, and ranger presentations at the campground amphitheater. Also, there are ranger–led walks.

The seven–mile loop drive includes many of the best examples of what the monument has to offer. There are cinder and spatter cones, lava tubes, fissure vents and overlapping lava flows.

The trail from North Crater Flow crosses Blue Dragon Lava Flow – formed some 2,200 years ago. The name comes from its surface lava, which is a bluish–purple obsidian. There are examples of three kinds of lava flow: pahoehoe (ropey looking), aa (jagged with sharp edges), and block lava. The trail also leads you to a 2,300 year old, 400 foot tall cinder cone volcano.

There is the Big Craters–Spatter Cones parking area, and the Devil's Orchard, with lava–transported cinder cone fragments.

Inferno Cone Viewpoint is atop a cinder cone, and offers views of the whole national monument. That view includes many spatter cones, the Great Rift Fissure, and the 800 foot tall, 6,000 year old Big Cinder Butte, which is a rare basaltic cone.

Craters of the MoonTree molds are found where lava flows moved slowly through a forest. As the trees burned they released enough water to cool the lava immediately surrounding them – forming tree casts.

Caves Trail leads to several lava tubes. Exposed to the air, the surface lava cooled and hardened while the molten rock was still flowing underneath. Sometimes the lava drained out the lower end, leaving a hollow tube.

If you go exploring any of the lava tubes, heed this advice: Don't go alone; do wear long pants and sturdy hiking shoes or boots; do bring a flashlight with good batteries. Watch your head because some of the tubes have low ceilings, and the rock is harder than your skull.

Indian Tunnel is especially good because its 800 feet long, 30 feet high, 50 feet wide, and has enough ceiling collapses so that you don't need a flashlight.

All the tubes are interesting, but Boy Scout Cave is special because it has year–round sheet ice on the floor that is covered with several inches of water. It's a slick place.

While it's true that the harshness of the landscape may not appeal immediately to everyone, a few hours of exploring this unique area – and learning about it – can result in a greater understanding of the place we call home. Craters of the Moon shows us the makings of planet earth – in all its violence and raw beauty.

The national monument isn't on any particular main highway, but if you're traveling anywhere near it, a one or two–day detour is well worth the time.

The American west has many unusual and fascinating destinations.

Craters of the Moon National Monument is certainly one of them.