1493–1600 Modern horses were first brought to the Americas with the
conquistadors, beginning with
Columbus, who imported horses from Spain to the
West Indies on his second voyage in 1493. Horses came to the mainland with the arrival of
Cortés in 1519. By 1525, Cortés had imported enough horses to create a nucleus of horse-breeding in Mexico. One hypothesis held that horse populations north of Mexico originated in the mid-1500s with the expeditions of
Narváez,
de Soto or
Coronado, but it has been refuted. Horse breeding in sufficient numbers to establish a self-sustaining population developed in what today is the
southwestern United States starting in 1598 when
Juan de Oñate founded
Santa Fe de Nuevo México. From 75 horses in his original expedition, he expanded his herd to 800, and from there the horse population increased rapidly. While the Spanish also brought horses to Florida in the 16th century, the
Choctaw and
Chickasaw horses of what is now the
southeastern United States are believed to be descended from western mustangs that moved east, and thus Spanish horses in Florida did not influence the mustang.
17th- and 18th-century dispersal s. Other horses were traded by Oñate' settlers for women, or food and other goods. Initially, horses obtained by Native people were simply eaten, along with any cattle that were captured or stolen. But as individuals with horse-handling skills fled Spanish control, sometimes with a few trained horses, the local tribes began using horses for riding and as pack animals. By 1659, settlements reported being raided for horses, and in the 1660s the "Apache" were trading human captives for horses. The
Pueblo Revolt of 1680 also resulted in large numbers of horses coming into the hands of Native people, the largest one-time influx in history. The
Eastern Shoshone and
Southern Utes became traders who distributed horses and horse culture from New Mexico to the northern plains. West of the
Continental Divide, horses distribution moved north quite rapidly along the western slopes of the
Rocky Mountains, skirting desert regions Estimates of when the peak population of mustangs occurred and total numbers vary widely between sources. No comprehensive census of feral horse numbers was ever performed until the time of the
Wild and Free-Roaming Horses and Burros Act of 1971 and any earlier estimates, particularly prior to the 20th century, are speculative. Some sources simply state that "millions" of mustangs once roamed western North America. In 1959, geographer Tom L. McKnight suggested that the population peaked in the late 1700s or early 1800s, and the "best guesses apparently lie between two and five million". Historian
J. Frank Dobie hypothesized that the population peaked around the end of the
Mexican–American War in 1848, stating: "My own guess is that at no time were there more than a million mustangs in Texas and no more than a million others scattered over the remainder of the West." J. Edward de Steiguer questioned Dobie's lower guess as still being too high. In 1839, the numbers of mustangs in Texas had been augmented by animals abandoned by Mexican settlers who had been ordered to leave the
Nueces Strip.
Ulysses Grant, in
his memoir, recalled seeing in 1846 an immense herd between the
Nueces River and the
Rio Grande in Texas: "As far as the eye could reach to our right, the herd extended. To the left, it extended equally. There was no estimating the number of animals in it; I have no idea that they could all have been corralled in the state of
Rhode Island, or
Delaware, at one time." When the area was
ceded to the U.S. in 1848, these horses and others in the surrounding areas were rounded up and trailed north and east, resulting in the near-elimination of mustangs in that area by 1860. the only horse sign he spoke of in the Great Basin, which he named, was tracks around
Pyramid Lake, and the natives he encountered there were horseless. In 1861, another party saw seven free-roaming horses near the
Stillwater Range. For the most part, free-roaming horse herds in the interior of Nevada were established in the latter part of the 1800s from escaped settlers' horses.
20th century In the early 1900s, thousands of free-roaming horses were rounded up for use in the
Spanish–American War and
World War I. By 1920, Bob Brislawn, who worked as a
packer for the U.S. government, recognized that the original mustangs were disappearing, and made efforts to preserve them, ultimately establishing the
Spanish Mustang Registry. In 1934, J. Frank Dobie stated that there were just "a few wild [feral] horses in Nevada, Wyoming and other Western states" and that "only a trace of Spanish blood is left in most of them" remaining. Other sources agree that by that time, only "pockets" of mustangs that retained Colonial Spanish Horse type remained. By 1930, the vast majority of free-roaming horses were found west of Continental Divide, with an estimated population between 50,000 and 150,000. They were almost completely confined to the remaining
United States General Land Office (GLO)-administered public lands and
National Forest rangelands in the
11 Western States. In 1934, the
Taylor Grazing Act established the
United States Grazing Service to manage livestock grazing on public lands, and in 1946, the GLO was combined with the Grazing Service to form the
Bureau of Land Management (BLM), which, along with the
Forest Service, was committed to removing feral horses from the lands they administered. By the 1950s, the mustang population dropped to an estimated 25,000 horses. Abuses linked to certain capture methods, including hunting from airplanes and poisoning water holes, led to the first federal free-roaming horse protection law in 1959. This statute, titled "Use of aircraft or motor vehicles to hunt certain wild horses or burros; pollution of watering holes" popularly known as the "Wild Horse Annie Act", prohibited the use of motor vehicles for capturing free-roaming horses and burros. Protection was increased further by the
Wild and Free-Roaming Horses and Burros Act of 1971 (WFRHABA). The
Wild and Free-Roaming Horses and Burros Act of 1971 provided for protection of certain previously established herds of horses and burros. It mandated the BLM to oversee the protection and management of free-roaming herds on lands it administered, and gave U.S. Forest Service similar authority on National Forest lands. and the
National Park Service, but for the most part they are not subject to management under the Act. A census completed in conjunction with passage of the Act found that there were approximately 17,300 horses (25,300 combined population of horses
and burros) on the BLM-administered lands and 2,039 on National Forests.
21st century 's
State Quarter, featuring the mustang The BLM has established
Herd Management Areas to determine where horses will be sustained as free-roaming populations. The BLM has established an Appropriate Management Level (AML) for each HMA, totaling 26,690 bureau-wide, but the on-range mustang population in August 2017 was estimated to have grown to over 72,000 horses, expanding to 88,090 in 2019. Another 45,000 horses are in holding facilities. ==Land use controversies==