Was it the drying, warming climate that pushed the ancient farmers off their fertile mesas to live within the canyons, or was it a defensive maneuver to meet the threat of raids and other violent conflict? And the more typical question: Where did they go when they departed? For some visitors, those are diverting, and safely distant, concerns. Others may find societal distress and a changing climate rather more immediate. As for me, I’m a little at odds. I may travel to escape, say, political news, for a time: the therapy of forgetting. But in that case, Bears Ears would be a curious choice just now.

The series of ruins we encountered on the trail to Fish Mouth Cave, despite their evocative power, are modest examples. A common estimate is that the Bears Ears region includes several hundred thousand archaeological sites — arguably the most intense concentration in North America, and perhaps in the world.

That evidence of successive waves of human settlement begins with hunter-gatherers who pursued mammoths and mastodons here some 12,000 years ago, as the last ice age receded, and on through the inflows and ebbs of cliff dwellers who occupied the area until around 1300 A.D. Much of that span is on view even to casual, astonished visitors like us. That is Bears Ears’ glory as a travel destination, and its vulnerability.

On our drive out to blacktop at the end of the day I was reminded, and not for the last time, that archaeology and anthropology are close cousins. We reached a T-junction. One way led north toward the town of Blanding, population about 3,600, whose welcome sign proclaims that it was “Established 1905.” That hearkens to its incorporation by a late-arriving tribe of pioneers of European origin. Many of their descendants here in San Juan County are among the most tenacious opponents of the national monument.

“You just don’t take something from somebody,” Phil Lyman, a San Juan County commissioner, told a New York Times reporter in May. He equated the monument designation to grand theft. “From a principle standpoint, this needs to go away,” he said. “I agree with President Trump: This never should have happened.”

If you plan a vacation that takes in the landmarks of contemporary local cultures, then, you can visit Recapture Canyon, near Blanding. It has many important cliff-dweller sites, but it is also a local all-terrain-vehicle playground. Vandalism and pothunter looting were so common here that in 2014 the Bureau of Land Management, the federal agency responsible for managing most of these lands, closed an illegal track that A.T.V. enthusiasts had bulled into the canyon. Hikers and horse riders were still permitted.