Massacre Rocks State Park in southeastern Idaho preserves a dramatic line of boulders along the Snake River that became a feared landmark on the Oregon and California trails. Emigrants called the narrow passage Devil’s Gate and Gate of Death because they dreaded attack, though the best-documented bloodshed occurred east of the rocks on August 9 and 10, 1862, when clashes between settlers and Shoshone killed at least eight settlers and at least 20 Shoshone. The site also includes Register Rock, where travelers carved their names, and a landscape shaped by volcanic activity and the Bonneville Flood about 14,500 years ago.