Cannonball Concretions

Cannonball Concretions is a roadside geological stop in the North Unit, about five miles along the scenic drive and across from Juniper Campground. Round, mineral-cemented rocks jut out of the pale badlands slopes. It's an easy, memorable stop if you want to see something odd without planning a hike. Allow 5 to 15 minutes to view the formations and exhibit; the pullout has car, bus and RV parking, including accessible spaces.

An accessible sidewalk gives you a view of the boulders and interpretive exhibit. Beyond it, the formation area is unpaved, loose and uneven, and can be slippery. The rocks themselves can be slick to climb, so take your time and look from stable ground. Pets aren't allowed on this activity; service animals are permitted on a leash no longer than six feet.

Mineral-rich water moves through porous badlands layers and leaves minerals in gaps between sediment grains, often around a core. Those minerals cement the grains together; more layers build outward, like a pearl. Erosion wears away the softer material and exposes the harder rounded stones. Some are several feet across, with reported examples reaching about five feet.

Frame one of the spheres against the ribbed clay and broken layers behind it. The round outline stands out more clearly beside that rough backdrop than in a tight crop of stone alone.

The pullout also gives access to the Buckhorn Trail, listed at 11.4 miles. Treat it as its own hike, not a quick extension to the rock stop; check the full route and conditions before setting out.