To the northwest of American Falls
is the Great Rift Natural Landmark, a network of fresh-looking laval flows and deep rifts that extend at least 800 feet into the earth. The best way to reach the area is to take Hwy 39 north toward Aberdeen
, then head west at the sign for the landmark.
The landmark was established in 1968 and represents the longest rift system in the United States, as well as the world's deepest.
To explore the Great Rift area, the BLM Idaho Falls District office can help.