"Without the roadless rule, protection of these national forests would be left to a patchwork management system that in the past resulted in millions of acres lost to logging, drilling and other industrial development," said Jane Danowitz, director of the Pew Environment Group's U.S. public lands program.
The U.S. Forest Service manages more than 190 million acres.
The court precedent could affect other land policies, including the Bureau of Land Management's currently unfunded "wildlands" order, which Utah has sued to block.
Southern Utah Wilderness Alliance attorney Heidi McIntosh said the ruling makes clear that federal land managers can preserve some lands under their multiple-use mandates.
"It's a pretty definitive statement," she said.
Utah officials had hoped Wyoming would prevail, said John Harja, director of Gov. Gary Herbert's Public Lands Policy Coordination Office. Federal foresters in Utah, he said, need better access to fight tree-killing bark beetles.
But the forest roadless rule is different than the wildlands policy because it went through an appropriate rule-making process, Harja said. "We always say if you're going to do something, do it right."
Wyoming attorneys argued the definition of roadless lands is synonymous with wilderness, which only Congress may designate. The U.S. Department of Agriculture and environmental groups said the designations are different, with roadless areas open to some mineral development and wheeled recreation.
Conflicting federal court rulings have upheld and overturned the road-building ban. The California-based 9th U.S. Circuit Court of Appeals threw out a 2005 Bush administration policy that opened some of the roadless areas to potential development. Rules affecting Idaho and Alaska are the subjects of separate challenges.
Tribune reporter Brandon Loomis contributed to this story.