RENO, Nev. (AP) — A 15-year-old legal battle between a Nevada county, the U.S. government and environmentalists resumed Monday in federal court in Reno, where Elko County officials once again are trying to prove a national forest road belongs to them based on claims it existed before the national forest was created more than a century ago.

Lawyers for The Wilderness Society called their first witness Monday in what's expected to be a weeklong evidentiary hearing before U.S. District Judge Miranda Du. They say there's no record of any road along the Jarbidge River before the area near the Idaho line was placed in reserve in 1905 and formally designated part of the Humboldt National Forest by President Teddy Roosevelt in 1909.

The case dates to when the U.S. Forest Service first sued Elko County in 1999 to halt reopening of the washed-out road for fear of harm to the threatened bull trout.

Legal arguments center on the interpretation of an 1866 law that established so-called RS 2477 roads by granting states and counties the right of way to build highways on federal lands. Congress repealed such right of ways in 1976, but it recognized those roads that were established on lands before national forests were formed or the land was placed into a federal reserve.

Elko County's lawyers maintain the Jarbidge South Canyon Road enjoys such status because miners and ranchers traveled the route in the 1890s. Environmentalists disagree.

"The question is not whether anyone ever set foot in the Jarbidge Canyon before the land was reserved," said Michael Freeman, a Denver-based lawyer for The Wilderness Society.

Rather, he said, the county must prove a highway formally was established under Nevada law before the land was placed in reserve.

County officials "speculate people must have created a trail," he said. "But there's simply no historic document — not a single map — that shows a trial or road there before 1909."

Elko County claims the road effectively was established by continuous use before 1909. District Attorney Gary Woodbury said the environmentalists rely on the flawed assumption that "if it didn't get written down, it didn't happen."

"The recorded facts are only the tip of the iceberg," Woodbury said. American Indians who lived in the region for 10,000 years traveled through the canyon to gather pine nuts and fish for salmon in winter months when they couldn't hunt for deer or mountain sheep, he said.

"The reasonable conclusion is the Indians went in South Canyon to get food," Woodbury said.

Likewise, miners and prospectors already were scouring the Jarbidge River for gold, he said.

"The notion that prospectors were stupid, uneducated people who just went hither and yon is nonsensical," Woodbury said. "There is a structure to the way miners and prospectors work. If you find gold in a stream, you go back upstream to see where it came from."

The case is unusual because while the U.S. government denies Elko County has established a right of way, the Forest Service signed a settlement agreement in 2011 that included its assurances it no longer would challenge the county's claim it exists.

The Wilderness Society and Great Old Broads for Wilderness sued to block the deal, saying U.S. officials lacked the authority to cede control of the road and shirk their responsibility to protect the fish. The groups filed their latest request earlier this year to re-establish federal authority over the road.