This Strange Wyoming Formation Looks Like Someone Dropped Utah in Middle of Cattle Country

Hells Half Acre, Wyoming

We’ve all driven past weird roadside stuff without stopping, but Hell’s Half Acre might be your biggest Wyoming miss yet. The name’s a total lie though – it’s hundreds of acres of the wildest rock formations you’ll ever see.

Native Americans avoided it, “Starship Troopers” filmed here, and some years back, you could scarf down a burger while literally staring into “hell.” Next time you’re between Casper and Shoshoni, do yourself a favor and pull over.

Hell’s Half Acre Is Actually 320 Acres

Sitting in Nacrona County, Hell’s Half Acre covers 320 acres (despite its name) of weird, moon-like terrain about 40 miles west of Casper along US 20/26. This spot features a maze of deep ravines, caves, and unusual rock formations.

The area is a huge depression in the earth, with jagged spires and rock columns rising from its base. You can walk paths that wind through these formations for an up-close look at nature’s handiwork.

As of July 2021, the area was fenced off, but two gates allow vehicular access to a gravel lot for viewing the topography.

A Lost Cowboy Named This Place

People used to call this place “The Devil’s Kitchen,” “The Pits of Hades,” and “The Baby Grand Canyon.” The name that stuck came from a lost cowboy who said he’d been riding through “hell’s half acre” all day. The name caught on, even though the area is much larger than half an acre.

The Geological History is Pretty Epic

The site is part of what geologists call the Lysite Member of the Wind River Formation. Water and wind carved this 150-foot-deep gorge over millions of years.

The Wind River Formation, which includes the Lysite Member, contains rocks that range in age from Paleocene to Cambrian.

The pinks, reds, and whites come from various minerals deposited over time, mostly siltstone, claystone, and sandstone.

Rock Layers Meet at Strange Angles

One cool feature at Hell’s Half Acre is what geologists call an “angular unconformity.” This happens when two rock layers meet at different angles. The Lysite Member contains angular unconformities that reveal shifts in Earth’s geological history during fault movements on the Casper Arch.

The folding and thrust faulting, are attributed to the Laramide Orogeny, a significant mountain-building event that shaped much of western North America.

Native Tribes Used This as a Buffalo Jump

Native tribes used Hell’s Half Acre as a hunting site long before settlers arrived. The ravine’s 180-foot drop worked as a “buffalo jump”, a hunting method (dates back as far as 12,000 years) where tribes would drive buffalo herds over the edge.

Hunters would wear wolf or buffalo calf hides to guide the animals toward the drop. Tribe members waiting below would then finish the hunt. This method let tribes gather enough meat for harsh Wyoming winters, making this site important to local cultural history.

Hunters Left 3000-Year-Old Artifacts

A 2006 dig at Hell’s Half Acre uncovered bison bones and spear points dating back 3,000 to 1,200 years. These finds backed up tribal stories about the area being an important hunting ground for thousands of years.

Researchers also found remains of temporary camps and butchering tools made from local stone. Fire-cracked rocks indicate that ancient peoples may have cooked or processed meat at the site after a successful hunt.

Tiny Ancient Horses Once Lived Here

The Wind River Formation is packed with fossils of ancient mammals. During the Eocene epoch (56 to 34 million years ago), Wyoming was warmer and wetter. The region was home to tiny early horses no bigger than house cats, primitive tapirs, and early primates. Fossils attributed to early primates, such as Plesiadapiformes, have also been discovered in Eocene deposits.

This Place “Became” an Alien Planet

Hollywood came to Hell’s Half Acre in 1997 when “Starship Troopers” needed a location that looked like an alien planet called Klendathu.

The bare, strange terrain was perfect for director Paul Verhoeven’s vision of a hostile bug world. Film crews spent weeks shooting here, using the natural features as backdrops for battle scenes. Today, fans of the movie still visit the site to stand where the fictional Mobile Infantry fought the Arachnids.

It Used to Be a Full-Blown Tourist Attraction

Hell’s Half Acre once had a roadside restaurant and a small motel that were closed and demolished in 2005. An interpretive sign is located west of where the former restaurant stood.

The area is fenced to protect both visitors and the fragile landscape. You’ll find information signs explaining the geology and history, plus picnic tables for breaks.

Though you can’t hike into the formations freely anymore, viewing areas offer great photo spots from several angles.

Visiting Hell’s Half Acre, Wyoming

Right off US 20/26 between Casper and Shoshoni, you’ll find this alien wonderland. Most people spend about an hour here, making it a perfect Wyoming road trip stop.

Visit during spring or fall when there’s mild weather since summers can get hot, as high as 90°F. Consider combining your trip with stops at nearby Alcova Reservoir for water fun or Casper Mountain for hiking.

The town of Powder River has the closest services, but bring water and snacks as options are limited.