The Devil’s Gate Pass is all that remains of an extinct volcano. The prehistoric Bonneville Flood shaped the landscape of the area, rolling and polishing the huge boulders found throughout the park. The flood was caused when eroding waters broke through Red Rock Pass near the Idaho/Utah border.
Massacre Rocks State Park received its name from a grouping of boulders that created a narrow break through which the Oregon and California Trails passed. Emigrants, fearing that American Indians might be waiting in ambush, named the boulders "Massacre Rocks."
