Runningwater Formation
Stratigraphic range: Early Miocene (Hemingfordian) ~20.6–16.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Formation
Lithology
Primary	Sandstone
Other	Conglomerate
Location
Coordinates	42°24′N 103°00′W / 42.4°N 103.0°W / 42.4; -103.0
Approximate paleocoordinates	43°06′N 99°06′W / 43.1°N 99.1°W / 43.1; -99.1
Region	Nebraska
Country	United States
Runningwater Formation (the United States) Show map of the United States Runningwater Formation (Nebraska) Show map of Nebraska

The Runningwater Formation is a geologic formation in Nebraska. It preserves fossils dating back to the Hemingfordian of the Early Miocene of the Neogene period. The sandstones and conglomerates of the formation were deposited in a fluvial environment. The formation has provided many fossil mammals.

Among the following fossils have been found in the formation:^[1]

Mammals

Reptiles

• Macrochelys schmidti
• Rhineura marslandensis
• Sceloporus sp.

• List of fossiliferous stratigraphic units in Nebraska
• Paleontology in Nebraska

• Hunt Jr, Robert M.; Yatkola, Daniel A. (2020), "A new species of the amphicyonid carnivore Cynelos Jourdan, 1862 from the early Miocene of North America", Geodiversitas, 42 (5): 57–67, doi:10.5252/geodiversitas2020v42a5