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Wild Horse and Burro Quick Facts

Contact: Tom Gorey, BLM Public Affairs (202-912-7420)

Updated as of May 5, 2015

Wild Horse and Burro Population

The Bureau of Land Management estimates that 49,209 wild horses and burros (about 40,815 horses and 8,394 burros) are roaming on BLM-managed rangelands in 10 Western states, based on the latest data available, compiled as of March 1, 2014. (This compares to the 2013 estimate of 40,605 animals.) Wild horses and burros have virtually no natural predators and their herd sizes can double about every four years. As a result, the agency must remove thousands of animals from the range each year to control herd sizes.

The estimated current free-roaming population exceeds by more than 22,500 the number that the BLM has determined can exist in balance with other public rangeland resources and uses. The maximum appropriate management level (AML) is approximately 26,684.

Off the range, as of April 2015, there were 47,393 other wild horses and burros fed and cared for at short-term corrals and long-term pastures. (Specifically, there were 15,848 horses and 822 burros in short-term holding [for a total of 16,670 animals] and 30,723 horses in long-term pastures.  The combined figure of 47,393 animals in holding compares to the BLM's total holding capacity of 50,929.)  All wild horses and burros in holding, like those roaming Western public rangelands, are protected by the BLM under the 1971 Wild Free-Roaming Horses and Burros Act, as amended.

Wild Horse and Burro Acreage

In 1971, when Congress passed the Wild Free-Roaming Horses and Burros Act, these animals were found roaming across 53.8 million acres known as Herd Areas, of which 42.4 million acres were under the BLM's jurisdiction.  Today the BLM manages wild horses and burros in 179 subsets of these Herd Areas (known as Herd Management Areas) that comprise 31.6 million acres, of which 26.9 million acres are under BLM management.  For the answer to the question "What happened to the 'missing' 22.2 million acres on which wild horses and burros were found roaming?," see below.  Also, it should be noted that under the 1971 Act, horses and burros may not be re-located to other public lands where they were not found roaming when the law was passed.

Wild Horse and Burro Budget

Congress appropriated $77.245 million to the Wild Horse and Burro Program in Fiscal Year 2014, which ended September 30, 2014. Of that year's program expenditures ($67.9 million), holding costs accounted for $43.235 million (64 percent); gathers and removals, $1.2 million (1.8 percent); and adoption events, $4.6 million (6.8 percent).  Other activities, such as monitoring Herd Management Areas, made up the balance.  (The $9.3 million difference between appropriations and expenditures is a result of the use of prior-year, contracted-related funding.)

Removing Wild Horses and Burros from the Range and Placing Animals in Adoption

To help ensure that herd sizes are in balance with other public rangeland resources and uses, the BLM removed 1,863 (1,695 horses and 168 burros) from the range in Fiscal Year 2014, which ended September 30, 2014.  (This figure compares to 4,176 animals removed from the range in FY 2013 and to 8,255 removed in FY 2012.)  The Bureau placed 2,173 removed animals into private care through adoption in FY 2014, as compared to 2,311 placed in FY 2013.  In contrast, 5,701 animals were adopted out a decade ago (FY 2005).  Since 1971, when Congress passed the Wild Free-Roaming Horses and Burros Act, the BLM has adopted out more than 235,000 horses and burros.  For more information about adoptions, please visit How to Adopt and the national adoption schedule.

Population Growth-Suppression Treatments

In Fiscal Year 2014, the BLM applied 384 fertility-control treatments to mares, 65 with PZP-22 and 319 with PZP (porcine zona pellucida, now known as ZonaStat H).

In FY 2013, the BLM applied 509 fertility-control treatments to mares, 310 with PZP-22 and 199 with PZP.

In FY 2012, the BLM applied 1,051 PZP fertility-control treatments to mares and released 180 more stallions than mares back into herds during gather operations, for a grand total of 1,195 population growth-suppression treatments in FY 2012. 


With regard to a call by advocacy groups for a moratorium on all BLM gathers of herds, this is untenable given the fact that herds grow at an average rate of 20 percent a year and can double in size every four years.*

* Eberhardt, L. L., Majorowicz, A. K. & Wilcox, J. A.  (1982).  Apparent Rates of Increase for Two Feral Horse Herds.  The Journal of Wildlife Management, 46(2), 367-374.

Garrott, Robert A., Siniff, Donald B. & Eberhardt, L. Lee.  (1991).  Growth Rates of Feral Horse Populations. The Journal of Wildlife Management, 55(4), 641-648.

Garrott, Robert A. & Taylor, Lynne.  (1990).  Dynamics of a Feral Horse Population in Montana. The Journal of Wildlife Management, 54(4), 603-612.

The ecosystems of public rangelands are not able to withstand the impacts from overpopulated herds, which include soil erosion, sedimentation of streams, and damage to wildlife habitat. As for the 1971 Wild Free-Roaming Horses and Burros Act, as amended, Section 1333 of that law mandates that once the Interior Secretary "determines...on the basis of all information currently available to him, that an overpopulation exists on a given area of the public lands and that action is necessary to remove excess animals, he shall immediately remove excess animals from the range so as to achieve appropriate management levels."

Sale Authority

About 8,400 wild horses and burros immediately became eligible for sale under the December 2004 sale-authority law (the so-called "Burns Amendment"), which directs the BLM to sell "without limitation" to any willing buyers animals that are either more than 10 years old or have been passed over for adoption at least three times. Since 2005, the Bureau has sold more than 5,500 horses and burros. It has been and remains the policy of the BLM, despite the unrestricted sales authority of the Burns Amendment, not to sell or send any wild horses or burros to slaughterhouses or to "kill buyers."

The proceeds from the sale of the eligible animals are used for the BLM’s wild horse and burro adoption program, as directed by Congress under the sale-authority amendment.

BLM’s Legal Mandates

The BLM manages the nation’s public lands for multiple uses, in accordance with the 1976 Federal Land Policy and Management Act. The Bureau manages wild horses and burros as part of this multiple-use mandate.

The BLM manages, protects, and controls wild horses and burros under the authority of the 1971 Wild Free-Roaming Horses and Burros Act (as amended by Congress in 1976, 1978, 1996, and 2004). This law authorizes the BLM to remove excess wild horses and burros from the range to sustain the health and productivity of the public lands.

Law Enforcement

In enforcing the 1971 Act, the BLM continues to work with law-enforcement authorities in the investigation and prosecution of those who violate this landmark law. The text of the law can be accessed here.


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2014 Wild Horse and Burro Herd Populations and Appropriate  Management Levels (AMLs) by State [population estimates as of March 1, 2014]




Max. AML































































Download Wild Horse and Burro Facility Reports:   FY-2015FY-2014,  FY-2013, FY-2012, FY-2011.

Video Clip:  Below is a two-minute video from June 2012 of the BLM's second annual tour of a pasture holding facility in El Dorado, Kansas. To view a larger version of this video, select this link.

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"What Happened to the 22.2 Million Acres?"

Frequently Asked Question: In 1971, wild horses and burros were found roaming across 53.8 million acres of Herd Areas, of which 42.4 million acres were under the BLM's jurisdiction. Today the BLM manages wild horses and burros in 179 subsets of these Herd Areas (known as Herd Management Areas) that comprise 31.6 million acres, of which 26.9 million acres are under BLM management. What happened to the 22.2 million acres on which these animals were originally found roaming?



Answer: No specific amount of acreage was “set aside” for the exclusive use of wild horses and burros under the 1971 Wild Free-Roaming Horses and Burros Act.  The Act directed the BLM to determine the areas where horses and burros were found roaming and to manage them "in a manner that is designed to achieve and maintain a thriving natural ecological balance on the public lands." The law also stipulated in Section 1339 that "Nothing in this Act shall be construed to authorize the [Interior] Secretary to relocate wild free-roaming horses or burros to areas of the public lands where they do not presently exist." Of the 22.2 million acres no longer managed for wild horse and burro use:

  • 6.7 million acres were never under BLM management.
  • Of the 15.5 million other acres of land under BLM management:
    • 48.6 percent (7,522,100 acres) were intermingled ("checkerboard") land ownerships or areas where water was not owned or controlled by the BLM, which made management infeasible; 
    • 13.5 percent (2,091,709 acres) were lands transferred out of the BLM's ownership to other agencies, both Federal and state through legislation or exchange;
    • 10.6 percent (1,645,758 acres) were lands where there were substantial conflicts with other resource values (such as the need to protect habitat for desert tortoise);
    • 9.7 percent (1,512,179 acres) were lands removed from wild horse and burro use through court decisions; urban expansion; highway fencing (causing habitat fragmentation); and land withdrawals; 
    • 9.6 percent (1,485,068 acres) were lands where no BLM animals were present at the time of the passage of the 1971 Act or places where all animals were claimed as private property.  These lands in future land-use plans will be subtracted from the BLM totals as they should never have been designated as lands where herds were found roaming; and
    • 8.0 percent (1,240,894 acres) were lands where a critical habitat component (such as winter range) was missing, making the land unsuitable for wild horse and burro use, or areas that had too few animals to allow for effective management.

The percentages above in this section were current as of July 25, 2011.  For more details, see maps and tables at this link.