Bureau of Land Management, Idaho.
The Great Rift is one of only two such features in the world. At 635 square miles, it is considered to be the largest, deepest, and most recent volcanic rift system in the continental United States. Many of Idaho`s most fascinating geological features lie along this potential wilderness. A tremendous fissure extending 65 miles opened up to emit successive lava flows some 15,000 years ago. This volcanic landscape with spatter caves, ice tubes, caves, and cinder cones awaits the adventurous desert hiker. It contains undisturbed and unusual geologic features throughout the 380,000 acres of the Craters of the Moon and Wapi lava flows. Abundant wildlife, including sage grouse, mourning doves, mule deer, and antelope, inhabit the area. Visitors can marvel at the scale-like formations of the Blue Dragon lava flow, hike the sharp and broken a`a lava of the Bear Park Kipuka, and explore lava tube caves inhabited as early as 1200 A.D.
From I-86 northeast of American Falls, take exit 40 and head northeast on ID 39 past American Falls Dam. After passing the dam, turn left on Center Pleasant Valley Road (2600 S) and drive about 7 miles east to Lava Bed Road. Turn right and drive north about 6 miles to Crystal Ice Cave Road. About a 6 mile drive on a dirt road will take you in the general vicinity of the Great Rift to a spot called "The Frying Pan."