Some 200 people turned out to protect a decision to close more than 2,340 acres of the Pine Nut mountains southeast of Gardnerville to protect fossil remains.
The Bureau of Land Management took the action last week to halt soil erosion and disturbance of the fossils by motorized vehicles.
The area remains open to non-motorized uses such as hiking, horseback riding and mountain biking. Main roads are to remain open to all traffic.
Four years ago, Derek Prosser, now 23, found 3-million-year-old mastodon bones while riding his motorcycle near his home next to the restricted area.
He said at Sunday's protest he turned his discovery over the to BLM after receiving assurance that the area would remain open.
"I took them to my home and I said, `I won't show them to you unless you promise not to shut down the Pine Nuts.' They promised me," he said. "I guess they thought I would forget after four years.
"This is a lot to blame on me. It's an emotional thing. I do not understand why they're doing this. I am really upset."
Participants at the rally said they didn't fault Prosser.
Bob Chaves, 77, of Johnson Lane, who has been riding motorcycles for nearly 60 years, said the closure would force families to give up an activity they love.
"Its freedom," he said "The kid did what he was supposed to do and we're being punished."
BLM spokesman Mark Struble said the federal agency would continue to work with trail users to find options to the closed area.
"We don't take any closure lightly," Struble said Sunday. "We realize that they are extremely unpopular. If we err on any side, it's that we let things stay open."