BLANDING, Utah — Fed up with federal control over lands their families have used for generations, dozens of Blanding residents — along with out-of-town supporters — Saturday drove ATVs into Recapture Canyon, a nearby trove of prehistoric sites the Bureau of Land Management closed to motorized use seven years ago.

San Juan County Commissioner Phil Lyman, acting as a private citizen, organized the event, which started with a rally in Blanding’s Centennial Park, to protest what he and more than 200 supporters called federal “overreach” into local jurisdiction.

Prompting the protest was BLM’s failure to process San Juan County’s applications for ATV rights of way in Recapture, although resentment with the federal agency here runs much deeper and wider than the canyon that parallels Blanding a few miles to the east.

BLM officials said they were disappointed demonstrators broke the law Saturday, adding that federal officers were present in the canyon recording riders and gathering evidence.

“We’re not proponents of breaking the law,” Lyman told reporters, an hour before joining dozens of riders on a closed route in defiance of federal law.

“This was a supervisor’s discretionary closure. It’s a county road. We claim it. If they can do that, what can they not do?”

But riding the canyon is unlawful, and conservationists expressed dismay that an elected leader would put himself above the law at the expense of the canyon’s irreplaceable cultural artifacts.

Under the watch of several horse-mounted sheriff’s deputies, some 50 ATVs carrying multiple riders, including children without helmets and militia members with weapons at the ready, motored across an invisible line in the dust where the canyon was off-limits.

“We are here to keep the peace and safeguard the constitutional rights of everybody,” San Juan County Sheriff Rick Eldredge said. “We don’t want to see clashes between citizens and clashes between BLM and militia. This is not going to be Bunkerville.”

The sheriff was referring to BLM’s recent standoff with armed supporters of Nevada rancher Cliven Bundy, who has long refused to pay grazing fees. Bundy’s son, Ryan, joined the protest ride into Recapture Canyon.

Part of a broad backlash against federal land management across the West, the ATV protest has attracted out-of-state activists eager to denounce federal authority over public lands. Some came decked in military camouflage and sidearms slung on their thighs. Militia men approached by The Tribune declined to be interviewed.

BLM had no visible presence at the north end of the canyon where riders entered on an established road below Recapture Reservoir, but they were there, according to BLM Utah director Juan Palma. He expressed concern that riders may have damaged artifacts and dwellings left by Ancestral Puebloans, who lived in the canyon until 800 years ago.

“As always, our first and most important priority is the safety of the public and our employees, and our actions today reflect that,” Palma said.