The Kiger Mustang is a rare strain of the Spanish Mustang. It is a descendant of the Spanish horses which were brought to Mexico by the Spanish conquistadores in the 17th century, and which found their way to the Great Basin in North America.

Since the 19th century, the people living in Eastern Oregon were aware of the local dun-colored Mustang population that roamed in the Steens Mountains. However, it was only in the 1970's that the Kiger Mustang was officially recognized as a pure strain of the Spanish Mustang. Since this discovery, wild herds of Kiger horses were carefully managed and bred by the Bureau of Land Management (BLM) to ensure the continuity of their pure Spanish blood.

Similarly to American Mustangs, Kiger Mustangs can also be adopted as part of the BLM's Adopt-A-Horse Program. Kigers are known for their comfortable temperament as well as for their intelligence, two qualities which make them relatively easy to adopt.

Kiger Mustangs are also renowned for their golden and noble appearance. For example, when working on the movie "Spirit: Stallion of the Cimarron", the producers decided to base the model of Spirit, their main character, on a Kiger Mustang stallion named Donner.

Kiger Mustangs have good endurance and a cow sense, and are therefore popular for endurance riding and for working with cattle, but they can also perform well in other disciplines. Kiger Mustangs are usually dun in color, though some can have primitive markings without the dun dilution. They usually stand between 13.2hh and 15.2hh, although some horses can reach 16hh.