Petrified Forest Loop

Petrified Forest Loop is a 10.3-mile circuit through the North and South Petrified Forest areas in the remote northwest of Theodore Roosevelt’s South Unit. It climbs from the badlands onto open prairie, visits both wood fields, and links them with a stretch of the Maah Daah Hey Trail. The route returns to the Petrified Forest Trailhead on a shared approach spur, so the total includes a short section walked both ways. Allow five to six hours; this is a half-day backcountry hike, not a quick walk from the parking area to one stump.

If you mainly want to see petrified wood, NPS also describes a roughly 3-mile round trip to either wood section, each about 1.5 miles from the parking area. Those are separate out-and-back visits. The full loop is for hikers who want both forests and the open country between them. If five or six hours in exposed terrain doesn’t fit your day, choose one section and return the same way.

The route drops from prairie into badlands valleys where trunks and stumps lie exposed among the eroded slopes. The North section has an optional climb up the far hillside for a view back over the wood. The South field is broader and more scattered; larger pieces are farther into it, and another climb reaches a plateau overlook. Take time to look around rather than treating the wood as a single photo stop: the two areas have different shapes and scale.

Expect an unmaintained tread with occasional uneven ground and loose stone. There’s little to no shade across the open sections, and wet clay can turn slick and cling to footwear. NPS recommends at least 1 litre of water per person per hour, especially in summer. Visitors also report that the long loop can be hard to follow in places, so check the route before leaving the trailhead and carry an offline map. Bison and wild horses roam the South Unit; sightings are a possibility, not a promise.

These are fossils, not ordinary fallen logs. More than 65 million years ago, swamp forests grew here among trees such as sequoias and bald cypress. Silica-rich groundwater later replaced the wood with quartz, sometimes preserving the grain and growth rings. The park describes its petrified wood as the third-largest concentration in the United States. Leave every piece where it is: removing petrified wood, rocks, or other park resources is illegal.

The trail begins at the lift gate behind the Petrified Forest Trailhead sign. The remote dirt-and-gravel approach takes about 50 minutes from Medora. Follow the marked Exit 10 route toward Camels Hump Lake; older West River Road directions lead onto private land. No food, toilet, or water source is listed for the trailhead, so arrive with what you need for the drive and hike. Pets aren’t allowed on this route.