Petrified Forest - South

Petrified Forest - South is a large concentration of fossilized tree trunks in Theodore Roosevelt National Park’s South Unit. It isn’t a roadside stop: the southern grove is about 1.5 miles from the parking area, so the out-and-back is about 3 miles. The trail climbs out of the badlands onto open prairie, then drops into a valley of petrified stumps. The full loop that links the north and south sections is 10.4 miles, a much bigger outing.

The southern concentration has slightly fewer stumps than the northern one, but the southeast wilderness view is the payoff here. Elk are often seen in that direction, so take a moment to look beyond the fossil wood. If you want the larger concentration, choose the north section; for this one, go for the view as well as the trees.

From Medora, plan on about 50 minutes over dirt and gravel roads. The park’s approved route begins at I-94 Exit 10 toward Camels Hump Lake; follow the marked posts and the park’s current directions to the trailhead. Older access instructions are out of date, and the destination pin marks the forest, not the parking area.

The slopes are steep in places, footing is loose and uneven, and the trail surface isn’t maintained. There’s little to no shade, and rain can leave the ground slippery. The park recommends at least a liter of water per person per hour, especially in summer. No food service, restroom, or potable-water source is confirmed at the trailhead, so treat this as a self-sufficient outing. Pets aren’t allowed on the trail.

Around 65 million years ago, this area was a flat, swampy delta as the Rocky Mountains formed. Sequoia, bald cypress, and magnolia grew here. In the water, the crocodile-like Champsosaurus gigas hunted among turtles, snails, and clams.

Sediment washed from the growing Rockies and quickly buried the trees. Mineral-rich water slowly replaced the trunks’ organic material, and later erosion exposed the petrified wood in the badlands. The park has the third-largest concentration of petrified wood in the United States, after Petrified Forest National Park and Yellowstone. Leave every stump and stone where you find it; removing park resources is illegal.

For a photo that shows what makes this stop different, include an exposed trunk against the pale eroded slopes. Then turn southeast for the broad wilderness view; elk are often seen in that direction.