The North and South Menan Buttes in southeastern Idaho are two of the world's largest volcanic tuff cones.

The buttes rise about 800 feet (250 m) above the surrounding Snake River plain and are late Pleistocene in age, dating to approximately 10,000 YBP (Years Before Present).

The US Bureau of Land Management designated the North Butte as an Area of Critical Environmental Concern (ACEC).

The volcanoes forming the two major Menan Buttes were created when basaltic magma came into contact with a shallow aquifer or with the precursor of the modern Snake River.

Particles of volcanic glass called tachylite were created as the water turned to steam and explosively fragmented the hot magma.