Eocene horses

Mesohippus (Greek: / meaning "middle" and / meaning "horse") is an extinct genus of early horse. It lived 37 to 32 million years ago in the Early Oligocene. Like many fossil horses, Mesohippus was common in North America. Its shoulder height is estimated at 60 cm.

Propalaeotherium was an early genus of perissodactyl endemic to Europe and Asia during the early Eocene. There are currently six recognised species within the genus, with P. isselanum as the type species (named by Georges Cuvier in 1824).

Eohippus is an extinct genus of small equid ungulates. The only species is E. angustidens, which was long considered a species of Hyracotherium (now strictly defined as a member of the Palaeotheriidae rather than the Equidae). Its remains have been identified in North America and date to the Early Eocene (Ypresian stage).

Miohippus (meaning "small horse") is an extinct genus of horse existing longer than most Equidae. It lived in what is now North America from 32 to 25 million years ago, during the late Eocene to late Oligocene. According to the Florida Museum of Natural History, Othniel Charles Marsh first believed Miohippus lived during the Miocene and thus named the genus using this incorrect conclusion. More recent research provides evidence that Miohippus actually lived during the Paleogene period.

Orohippus (from the Greek , 'mountain' and , 'horse') is an extinct equid that lived in the Eocene (about 50 million years ago). Its fossils have been unearthed in Oregon, Colorado, Utah, and Wyoming.

Epihippus is an extinct genus of the modern horse family Equidae that lived in the Eocene, from 46 to 38 million years ago.

Eurohippus is an extinct genus of equoid ungulate. Its species were long considered part of Propalaeotherium and Lophiotherium. A pregnant specimen was described in 2015.

Sifrhippus is an extinct genus of equid containing the species S. sandrae. Sifrhippus is the oldest known equid, living during the early Eocene. Its fossils were discovered in the Bighorn Basin of Wyoming.

Protorohippus (Latin: "before" (pro), + Greek: "mountain" (oros), "horse" (hippos)) is an extinct genus of equid that lived in the Eocene of North America.

thumb|left|Restoration of Haplohippus (middle right) and other animals of the Hancock Mammal Quarry Haplohippus is an extinct genus of the modern horse family Equidae, that lived in the Eocene, from 42 to 38 million years ago. Fossil remains of Haplohippus have been found in the Clarno Formation, part of the John Day Fossil Beds National Monument of the Northwestern United States. While Haplohippus is quite similar to Orohippus, it is considered more primitive in character than Epihippus.

Pliolophus is an extinct equid that lived in the Early Eocene of Britain.