Pronghorn antelope from Grand Teton National Park will always have access through the last unprotected bottleneck on their annual migration route thanks to a new easement, a conservation group said Monday.

The Conservation Fund said it has completed a deal to secure a conservation easement on 2,400 acres of the Carney Ranch in Sublette County. The ranch lies along the “path of the pronghorn,” which wends from the national park, up the Gros Ventre River, over the Kinky Creek Divide and into the Green River basin.

Biologists say the annual migration is the second longest annual terrestrial journey in the Western Hemisphere.

The easement prevents development and ensures sound management of the ranch, Conservation Fund state director Luke Lynch said. The ranch spans three miles of the Green River.

“This project protects the pronghorn and a working cattle ranch — two icons of the American West,” Lynch said. “The Carney family made a significant donation to make this possible — we applaud the three generations of family members for their major commitment to conservation.”

John Carney, a Jackson architect and former Teton County commissioner, is president of the ranch and the son of the late Otis Carney, whose lifelong goal was to protect the gem he discovered in 1963.

“To see this pristine land preserved for posterity was his dream,” Carney said in a statement. “He would be very pleased at this outcome.”

The property has been operated as a cattle ranch and will continue to be used that way. It straddles one of three bottlenecks on the migration route and is the last to be protected.

The bottlenecks are places where the sagebrush steppe is pinched by topography, vegetation or development. Short sight distances and obstructions might serve as a roadblock to the sometimes skittish pronghorn that have evolved in open country to rely on keen eyesight and blazing speed to elude predators.

The Conservation Fund purchased the easement using a wide source of funds. Some came from the Acres for America program, a partnership established between Wal-Mart Stores Inc. and the National Fish and Wildlife Foundation. The Jonah Interagency Office, Wyoming Landscape Conservation Initiative, the Wyoming Wildlife & Natural Resources Trust and The Nature Conservancy, through a grant from the Doris Duke Charitable Foundation, provided additional funding, Lynch said.

The Jonah Interagency Office is funded in part by gas revenue from the development of the Jonah Field in southern Sublette County. EnCana is the main partner in that effort, Lynch said.

Protecting the Carney Ranch has been a high priority for the Wyoming Game and Fish Department, as it provides habitat for 75 “species of greatest conservation need,” one of the highest counts ever recorded in the state. The initiative allowed the Carney family to buy the nearby DC Bar ranch, another 240 acres in the corridor that the Conservation Fund is actively working to protect, Lynch said.

The effort is in line with Wal-Mart’s vision, said Matt Kistler, the company’s senior vice president for sustainability.

“Conserving land and managing natural resources further supports our larger goal to bring sustainability into the communities we serve,” he said in a statement.