THE BLACK HILLS, S.D. -- The thunderous sound of hooves running through the prairie grass and sagebrush reaches the ear before the eye can see the wild mustangs kicking up dust and racing across this land that is as ruggged and wild as they are.

About 2,000 of these sturdy horses in the vast, gently rolling hills are part of scenic portrait that resembles the Old West of another era. Their home is the Institute of Range and the American Mustang, 47,000 acres of lush prairie in the southern Black Hills.

The institute is the brainchild of Dayton O. Hyde, a rancher from Chiloquin, Ore., and is the first federally funded sanctuary for wild horses. As a pilot project for the Bureau of Land Management (BLM), the sanctuary is an attempt to provide a humane home for increasing numbers of unwanted wild horses.

The steeds here are too old and wild to be tamed. Some are injured, and some have frostbitten ears or crooked limbs, which makes them unwanted and not sought for adoption.

Not all are candidates for the glue factory or retirement to government feedlots, corrals that were little more than open cages. Some of the wildest, most ornery horses are beautiful, with sinewy muscles and glistening coats of black, brown, silver-gray and white.

Horses here come from any of the nation's 10 federal land ranges, mostly in western states. They are among the 40,000 wild mustangs in the country, which is about 15,000 too many, according to the BLM.

In 1971, the Wild Free-Roaming Horse and Burro Act made it a crime to harm or kill the horses, which ensured their right to roam and reproduce on the range but gave excess mustangs no place to run free. The government had no alternative but to corral them in feedlots, the last of which was closed last year in Bloomfield, Neb.

About 70 percent of the excess mustangs and burros are adopted annually by private citizens for $125 each through a BLM program. How to deal with the other 30 percent confounded the agency until Hyde appeared in Washington two years ago with no briefcase, few contacts and a dream for getting the animals out of feedlots.

Hyde, 65, stands an imposing 6-foot-5 and has a John Wayne swagger and strong, deliberate speech. He learned to ride captured mustangs during his childhood in Oregon. In his trailer home on the floor of one of the sanctuary's many valleys, he recalled finding 40 wild horses starved to death in Oregon in 1939, and said, "I never got over that feeling of sadness when I saw them."

An author of a dozen wildlife books and novels and a specialist in wildlife conservation, Hyde approached the BLM after Congress had criticized the agency for spending too much money to maintain horses on feedlots. Land owners and ranchers also were expressing resentment about horses imposing on valuable grazing land. Last year, about 450 wild horses were found shot to death in Nevada, which has more than any other state.

Hyde established the institute as a nonprofit corporation that raises money from individuals, corporations and foundations to buy land and establish a permanent, privately owned sanctuary.

"This was the best option we had for unadoptable horses, and the program actually saves us money," said Mark Stiles, an area resource manager for the BLM in South Dakota.

The BLM, which used to pay $2.64 a day to maintain each horse in a feedlot, is paying Hyde $1 a day to feed and maintain each horse until next year when the sanctuary is expected to have enough funds to become self-sufficient.

Several hundred people visited this summer and paid $15 each for a guided tour. Hyde is planning a visitors' center and museum that would detail the horse's role and prominence in the settlement of North America.

Linda Fischer, 47, of Berkely, Ill., came to see wild mustangs for the first time last summer. "They are really beautiful and carefree," she said. "They're not skinny or ugly, and they really seem like they belong there."

Initially, Hyde said, he expected about 10 percent of horses at the sanctuary to die because of age and infirmities but has yet to see even a 1 percent death rate. Mustangs in feedlots often succumbed to parasites, diseases and broken spirits, he noted. At the sanctuary, they are free to graze on the straw-colored prairie, shelter under Ponderosa pines and juniper trees and drink from the Cheyenne River. To control the population, stallions are castrated before arriving. In winter, the horses may require occasional feeding, Hyde said, but the land generally takes care of them.

"I'd rather see fewer horses in great condition," Hyde said. "Starvation is a miserable way for an animal to die."

Sen. Harry Reid (D-Nev.), who supported startup funds for the project in the Appropriations Committee, called horses "symbols of freedom" and added, "This is a unique, impressive approach to dealing with them. It will help solve our problems with the horses in Nevada and, in general, provide a solution where fragile environments -- both the horses' and the ranchers' -- can coexist."

Hyde said he plans to raise funds to widen the sanctuary's borders and take in more horses. Mustangs now graze near Hell Canyon in the sanctuary where Honeywell Corp. planned to test experimental weapons before the land was purchased.

Sitting on a rimrock of an immense canyon overlooking the Cheyenne River that is to become site of the museum, Hyde expressed the reason for his passion about the project.

"I spend a lot of time here, sitting and observing," he said. "This is an incredibly great land, and sometimes you just have to take time to stop and smell the horses."