Massacre Rocks State Park

Massacre Rocks State Park is one of the Historical Areas operated by the State of Idaho to remind visitors of the march of history through the state.  Ten miles west of American Falls on I-86, take exit 28 and follow the signs.  The park has stories to tell which date back to times best described in geologic terms. A study of history indicates the park’s ominous name isn’t supported by actual events.  Devils Gate Pass gets undeserved credit as the scene of a wagon train ambush by natives.  It’s easy to see why the travelers feared an ambush at the narrow passage that is all that’s left of an extinct volcano.  But on August 9 and 10, 1862 it was an area east of Devils Gate, and even east of the park, which saw a series of skirmishes involving four wagon trains.  When it was over 10 pioneers and an unknown number of natives were dead and the area acquired it’s undeserved name.  Actually settlers and the natives made use of the area for generations because the Snake River is accessible and relatively gentle in this part of its run, and the violent episodes were the exception, not the rule.

Register Rock has Pioneer names etched into it.Compared to Massacre Rocks, Register Rock, also located within the park, is aptly named.  As travelers on the Oregon Trail paused at Register Rock, they succumbed to the all too human desire to leave word of their passage.  They inscribed their names and often the date of their passage on Register Rock.  Today the rock is protected by a weather shelter, which you are welcome to think was built for your benefit if it makes you feel better.  Look, but don’t touch.  Efforts to emulate the pioneers by leaving behind a bit of graffiti are unlawful and the law is strictly enforced.

Melon Gravel near Massacre Rocks - ISU Digital AtlasScattered through the Park, you’ll see huge boulders.  These are remnants of the fury of nature.  Until 14,500 years ago, a blink of the geologic eye, most of Utah and parts of Nevada were under the waters of Lake Bonneville.  When the natural dam could no longer contain the waters the torrent emptied almost the entire lake in a matter of months.  At one point the flow of water was four times that of the Amazon and the boulders you see today were ripped from mountainsides, smoothed by the flow and rolled in the flow for hundreds of miles to where you see them resting today.

Rainbow over the campground

Modern visitors have it easy compared to the earlier users of this area.  The park’s 900 acres offer a 50 unit campground with water and electrical hookups for RV’s, and a large overflow parking area for the more self sufficient.  You’ll also find rest rooms with hot showers, a picnic area, a boat launch, and a visitor center which provides advice and maps.  Between Memorial Day and Labor Day the park staff offers campfire programs scheduled to allow you to enjoy the park’s spectacular sunsets.  No need to hurry after that pot of gold at the end of the rainbow.

Visit our Birdwatching page.If high desert flora and fauna attract you, you’ll love Massacre Rocks State Park.  The park contains about 300 species of plants, and bird watchers have reported over 200 species of birds.  If you are looking for the birds not usually seen back home keep an eye out for whistling swans, bald eagles, pelicans and blue herons, all of which are commonly seen.

Massacre Rocks Visitor's Center MuseumOur Visitor’s Center
Massacre Rocks State Park is one of the Historic Areas operated by the State of Idaho to remind visitors of the march of history through the state. The park has stories to tell which date back to times best described in geologic terms.
View our ArcGis Interactive Trail Map.


Park Ln, American Falls, ID 83211


42.676686088608, -112.98518032129


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