|Massacre Rocks State Park|
IUCN category V (protected landscape/seascape)
Massacre Rocks, viewed from the visitor center
|Location||Power County, Idaho, United States|
|Nearest city||American Falls, Idaho|
MASSACRE ROCKS STATE PARK Latitude and Longitude:
|Area||990 acres (4.0 km2) |
|Elevation||4,400 ft (1,300 m) |
|Designation||Idaho state park|
|Administrator||Idaho Department of Parks and Recreation|
|Website||Massacre Rocks State Park|
Massacre Rocks State Park is a history-focused public recreation area in the Northwest United States featuring the Massacre Rocks, a famous spot along the Oregon Trail and California Trail during the middle 19th century. The state park is located along the Snake River, ten miles (16 km) southwest of American Falls, in Power County, Idaho. 
The park features a configuration of boulders along the south bank of the Snake River, known alternatively as Massacre Rocks, "Gate of Death", or "Devil's Gate". Emigrants gave this name to the narrow passage of the trail through the rocks, from the fear of possible ambush by Native Americans. According to diaries of emigrants, settlers in five wagons clashed with Shoshoni just east of the rocks on August 9–10, 1862. Ten emigrants died in the fight, which involved four wagon trains. The skirmishes took place east of the park and not at Devil's Gate as commonly believed. Some confrontations may have occurred there, but they remain unverified.  The Clark Massacre of 1851 occurred just west of Massacre Rocks, closer to the Raft River.
The rocks were often used as campsite for wagon trains along the trail. Many emigrants carved their names and dates on Register Rock, which is now protected by a shelter.  The actual passage through the rocks is now the route of Interstate 86 along the south edge of the park.
Geologically, the park was created during the repeated volcanic activity on the Snake River Plain. The rocks themselves were deposited in their present location at the end of the last ice age, approximately 14,500 years ago, during the catastrophic flood known as the Bonneville Flood, when much of Lake Bonneville surged down the Snake River.  A notch in the cliff on the north bank of the Snake opposite the park was the site of an ancient waterfall of a side channel of the waters in the aftermath of the flood.
The park is accessible by automobile on Interstate 86 and by foot using a trail from the rest areas just east of the park on Interstate 86. The footpaths also provide access to remnants of the original Oregon Trail on the south side of the highway. Exhibits in the park's visitor center describe the history and geology of the park. The park offers trails for hiking and biking, disc golf course, campground, and access to the Snake River. 
- "Massacre Rocks State Park". Geographic Names Information System. United States Geological Survey.
- "Massacre Rocks State Park". Idaho Parks and Recreation. Retrieved October 16, 2018.
- "History: State Lands in Idaho". Idaho Museum of Natural History. Retrieved March 5, 2011.
- "Massacre Rocks". Digital Atlas of Idaho. Idaho Museum of Natural History. Retrieved March 5, 2011.
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