| Named By: | Joseph Leidy in 1856 |
| Time Period: | Miocene |
| Location: | Across Mexico and the USA |
| Size: | Size depends upon the species in question. Usually credited as being around 1 meter high at the shoulder estimates reach to as much as 1.8 meters tall at the shoulder |
| Diet: | Herbivore |
| Fossil(s): | Multiple specimens |
| Classification: | | Chordata | Mammalia | Perissodactyla | Equidae | Equinae | |
Merychippus is an extinct proto-horse of the family Equidae that was endemic to North America during the Miocene from 20.43--10.3 Ma living for approximately 10.13 million years.
It had three toes on each foot and is the first horse known to have grazed. Its name means "ruminant horse", but current evidence does not support Merychippus ruminating.