Stone Trees
Buried in the
Badlands

This Was Once Coastal Georgia, Not North Dakota

The National Park Service dates the fossil forest to roughly sixty five million years ago, shortly after the extinction event that wiped out the dinosaurs, when this part of North Dakota was a flat, swampy river delta rather than an eroded badland. The North Dakota Geological Survey places the broader window a bit more precisely, spanning the Paleocene epoch from about sixty seven to fifty five million years ago, and describes an environment that would have resembled coastal Georgia or Mississippi: meandering rivers, everglade-like swamps, and floodplain forests of trees up to twelve feet across and over a hundred feet tall. Sequoia, bald cypress, and magnolia grew here, alongside animals like the crocodile-relative Champsosaurus, turtles, snails, and clams, all of it buried under sediment washed down from the growing Rocky Mountains to the west.

Speed Is the Whole Trick

Petrification requires rapid burial, fast enough that normal decay never sets in. Once a fallen tree was sealed under sediment here, mineral-rich groundwater moved through it, and silica in that water slowly replaced the wood's organic material, cell by cell, while preserving the original structure closely enough that growth rings are still visible in cross-section today. Traces of other minerals decided the color: iron produced yellows, browns, and reds, while carbon or manganese produced blacks and purples. The rock layers holding all of this, geologists call them the Bullion Creek and Sentinel Butte formations, also contain beds of volcanic tuff, meaning actual compacted ash fell into this delta while the forest around it was still alive.

Not a Roadside Stop

The trailhead sits off a separate access road from Interstate 94's Exit 10, roughly fifty minutes from Medora on dirt and gravel, not along the main South Unit Scenic Loop. The trail itself is unpaved and unmaintained, with steep slopes, uneven footing, and little shade, and the National Park Service recommends carrying at least a liter of water per person for every hour on foot. No pets are allowed, no permit is required, and the route crosses two separate sections where petrified stumps and logs are visible directly in the ground. The payoff for the extra effort is real: the Park Service states this park holds the third-highest concentration of petrified wood in the country, behind only Petrified Forest National Park in Arizona and Yellowstone.

A Different Forest From Arizona's

Arizona's Petrified Forest National Park preserves trees from the Late Triassic, roughly two hundred eight to two hundred twenty three million years ago, part of the world dinosaurs were just beginning to inherit. What's scattered across this trail in North Dakota is Paleocene, formed after dinosaurs were already gone, from an unrelated delta system entirely. Federal regulation treats both the same way regardless of age: removing, digging up, or disturbing petrified wood in any national park is prohibited under park rules covering natural resources, with no personal-souvenir exception the way there sometimes is for berries or nuts. Whatever you find on this trail belongs exactly where you found it, the same rule Arizona's rangers have spent decades trying to enforce against a much larger crowd of visitors than this quieter park has ever had to manage.

Facts and figures checked against the National Park Service's Petrified Forest South places page, the NPS Geodiversity Atlas for Theodore Roosevelt National Park, the North Dakota Geological Survey's petrified wood page, the NPS "Hike the Petrified Forest" page, and 36 CFR 2.1 for federal removal restrictions. Trail mileage varies by route option on the NPS page and isn't stated here as a single figure; check current conditions before hiking. No park-specific enforcement incident is cited here, since none could be independently verified for this park.

Round that same bend again on the way out and the stumps are still there, unchanged, doing exactly what stone does. They'll look the same in another hundred years, and in another million, long after every visitor who walked this trail today is gone the way the actual trees went, slowly, then all at once, sealed under sediment before decay ever got the chance to finish the job.