Badlands National Park and its changing layers of earth
Published on 09/23/2026 at 04:45 | Editorial responsibility: Rafael Müller, Editor-in-Chief AD HOC NEWS
Badlands National Park spreads across sharply eroded ridges, pinnacles, gullies and buttes near Interior in South Dakota. Its exposed layers preserve a record of changing landscapes, from a shallow inland sea to river floodplains and grasslands.
The colours and textures are not decorative details added to a single landscape. They are visible parts of a geological record extending across roughly 75 million years.
Badlands National Park: a landscape built from layers
The oldest exposed rocks belong to the Pierre Shale, deposited between about 75 and 69 million years ago beneath the Western Interior Seaway. This dark marine mud contains fossils from animals that lived in the ancient sea.
Later strata record land environments. The Chadron Formation contains river and floodplain deposits from the Eocene, while the Brule Formation belongs to the Oligocene. Higher layers include the Sharps Formation, formed from sediment, sand and volcanic ash.
The geological formations of the park appear as bands across the buttes and ridges. Grey, tan, red, orange and yellow surfaces mark differences in sediment, soil and mineral content.
From inland sea to fossil country
The Western Interior Seaway covered much of the Great Plains during the Late Cretaceous. As the sea disappeared, forests and floodplains occupied the region, followed by savannah and open grassland as the climate changed.
The fossil record reflects these environments. Marine layers preserve evidence of ancient sea life, while younger deposits contain mammals from the Oligocene, including three-toed horses, camels and early rhinoceroses.
Badlands National Park became a national monument in 1939 and a national park in 1978. Paleontological resources were central to the area’s protection, and fossil research remains closely linked with the park’s identity.
The National Park Service describes 75 million years of earth history within the exposed strata. Erosion began shaping the present badlands about 500,000 years ago.
Buttes, pinnacles and the living prairie
Badlands National Park is not only a collection of bare rock formations. Prairie surrounds the eroded formations, with grasses occupying spaces between walls, spires and sharply cut valleys.
The park’s geological deposits also support a record of changing climate. Fossilised soils appear among the rock layers, and their colours preserve information about ancient vegetation and moisture.
The geology and paleontology of Badlands connect visible scenery with scientific study. Fossils gradually become exposed as sedimentary rock erodes, creating a landscape that changes through natural geological processes.
Several named areas give the park a recognisable visual vocabulary. The Badlands Wall forms a long line of eroded formations, while the Yellow Mounds display colourful weathered soils above darker marine layers.
Visiting Badlands National Park: what travellers from Western Europe should know
- Badlands National Park lies in south-western South Dakota, with Interior near the park’s western side. Road access connects the area with Interstate 90 and the surrounding Black Hills region.
- The terrain combines open prairie with steep-sided buttes, loose sediment and narrow gullies. Trails and viewpoints include uneven ground, exposed rock and changes in elevation.
- The park is in the Great Plains, where summer heat, strong sun and limited shade form part of the landscape’s permanent character.
- The official language is English and the currency is the United States dollar.
- Entry requirements depend on your nationality; UK travellers can check the FCDO travel advice at gov.uk/foreign-travel-advice, Irish travellers the Department of Foreign Affairs at ireland.ie.
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Frequently asked questions about Badlands National Park
Where is Badlands National Park?
Badlands National Park is in south-western South Dakota, near the town of Interior. The park occupies a landscape of eroded formations and prairie.
What can visitors expect to see?
Visitors encounter layered buttes, pinnacles, gullies, colourful mounds and open grassland. Roads, overlooks and trails reveal the relationship between the rock formations and prairie.
What makes the park distinctive?
Its exposed strata preserve a geological record spanning roughly 75 million years. Marine fossils, fossilised soils and Oligocene mammal remains connect the scenery with ancient environments.
