Toadstool Geologic Park, Protected geological site in northwestern Nebraska, United States.

Toadstool Geologic Park is a protected geological site in northwestern Nebraska covering approximately 300 acres with distinctive rock formations shaped by wind and water erosion. The landscape features natural mushroom-like sculptures created when harder sandstone layers resist weathering while softer clay beneath gradually wears away.

The badlands layers were laid down by sedimentation from ancient volcanoes, then cut by erosion into the toadstool-shaped formations that give the park its name. Fossils of large prehistoric animals, among them entelodonts and hyaenodons, have been found in these beds. The park lies in the Oglala National Grassland and is run by the United States Forest Service.

The park's name comes from its mushroom-shaped sandstone formations, and the reconstructed sod house shows how Plains settlers built homes from cut prairie turf. The 1-mile loop trail passes fossil beds where entelodonts and hyaenodons were found; removing fossils is prohibited.

The park is open 24 hours a day and reached from Nebraska Highways 2 and 71 via Toadstool Road north of Crawford. A 1-mile loop trail runs through the formations, and the 3-mile Bison Trail crosses Whitehead Creek to the Hudson-Meng Bison Kill site. Camping is available and there are two toilets; no entry fee is charged.

The rock formations consist of sandstone caps balanced on clay pedestals, creating natural sculptures that resemble giant mushrooms. This unusual structure developed because the two rock layers erode at different rates.