Big Southern Butte is one of two rhyolitic domes rising from a sea of basalt near the center of the eastern Snake River Plain (of the nearby Twin Buttes, East Butte is rhyolitic and Middle Butte is basaltic). The area supports lodgepole pine, aspen, Douglas fir, and manzanita (not common to this region). The butte is one of the largest volcanic domes in the world but at 300,000 years old is also one of the youngest. Hikers who trek to the 7,550-foot high summit are rewarded with spectacular panoramic views. Approximate season of use is mid-May through October, depending on snow levels and road conditions. The road is open to full-sized vehicles, but it is best traveled by ATV or UTV. Please call the Upper Snake Field Office at 208-524-7500 for more information.