But the hopes, and the fears, about how that system might now change are boundless.

“My big hope is that people would be able to go back to work in San Juan County and these rural areas,” said Phil Lyman, a county commissioner in southern Utah, where antigovernment feelings run as deep as the slot canyons. “You just feel like everything has been stifled with regulations.”

At the Western Watersheds Project, a conservation group focusing on the Rocky Mountain region, legal teams are on deck and ready to fight back. “We’re getting ready for an onslaught of anti-environmental policy, and we’re arming up to litigate,” said Erik Molvar, the group’s executive director. “The Trump administration is going to find it very difficult to take away all of the federal laws which have been adopted over the past 40 years.”

In the decades-long struggle for control of America’s public lands, the Obama years were a flush time for conservation groups. The administration imposed moratoriums on uranium drilling near the Grand Canyon and blocked new coal leases. Public lands were also adapted for new uses on Mr. Obama’s watch, notably a wave of national monuments based around cultural or historical significance, and a big expansion of solar energy on federal lands in Nevada.

Conservatives who loathed those regulations — or new uses — are now hoping Mr. Trump shifts the balance decisively in their favor. Republicans in Congress have proposed bills weakening federal laws that protect wilderness, water quality, endangered species or that allow presidents to unilaterally name new national monuments. Some conservatives hope Mr. Trump will support their efforts to hand federal land over to states, which could sell it off or speed up drilling approvals.

To see where change may come the quickest, look to the edges of Glacier National Park in Montana, at a quilt of rocky peaks and wetlands held sacred by the Blackfeet tribe. In March, the Obama administration capped a three-decade fight over oil and gas drilling in the area, called the Badger-Two Medicine, by canceling a Louisiana energy company’s lease on 6,000 acres.

The company, Solenex, sued. A lawyer for the company, William Perry Pendley of the Mountain States Legal Foundation, said the incoming Trump administration could simply decide that canceling the lease had been wrong.

“All it would take,” he said, “is for the Justice Department to enter the case and say, ‘We’ve re-evaluated. We will lift the suspension and we’ll permit the drilling to go forward.’”