The first equid remains are reported from sediments at the late Miocene Ogallala stratotype locality (Joseph R Thomasson Site 9a=JRT Site 9a) of the Prolithospermum johnstonii-Nassella pohlii Assemblage Zone in Ellis County, Kansas. The two specimens were recovered from a diatomaceous marl unit approximately in the middle of the zone and consist of a right lower fourth premolar (Rp4) and a left third metatarsal of the grazing tridactyl equid Neohipparion eurystyle. The presence of Neohipparion eurystyle within this plant assemblage zone supports the suggestion of a savanna or savanna parkland in the region during deposition of the fossils and is evidence for a Miocene Hemphillian Land Mammal Age assignment for the stratum from which the fossils were recovered. Other fossils collected from the same stratum as the horses, including diatoms, a partial frog ilium, ostracods, charophytes, sedge rhizomes, and mollusks, indicate the presence of a pond.