“When will the legislature realize that the public does not want to see the Wasatch Mountains barricaded with ‘No Trespassing’ signs, the Book Cliffs lost to tar sand strip mines or Arches National Park ringed with oil and gas development?” he said in a statement.

The group launched a radio and television campaign this week aimed at drumming up opposition to the plan, describing it as a “land grab.” The ads allege that managing the lands would be so costly that Utah would be forced to sell or lease them to private developers.

“But that means Utahans would lose access to the lands that formed our heritage,” says the television ad, which shows people fishing and horseback riding. “Seizing public lands: A bad idea we can’t afford.”

Mr. Ivory dismissed the attacks as “fear tactics,” pointing out that the law includes only lands designated for multiple use — in other words, economic development — and not national parks or national monuments.

“They’re trying to get people to think that the sky is falling, and it’s just not,” Mr. Ivory said. “In fact, Utah passed the only state wilderness act so that, as the lands are transferred, we designate the unique heritage sites as state wilderness to be protected under the guidelines the state establishes.”

He pointed to the report, which he says shows “clearly Utah can afford to do this without selling off any land. None of that is contemplated.”

“These are tactics by those who just want to keep making money by suing the federal government,” Mr. Ivory said, referring to environmental groups.

He pointed out that transferring federal lands to state control has the support of the American Farm Bureau, the National Association of Counties and the Republican National Committee. A half-dozen Western states are expected to consider similar proposals in next year’s legislative session, while bills have been introduced in Congress to support the idea.

Former Interior Secretary Ken Salazar slammed the Utah legislation in 2012, saying it “defied common sense,” and accused lawmakers of playing politics.

As far as Mr. Ivory is concerned, however, shifting management to the states would be far preferable than keeping the lands under the increasingly tight control of the federal government.

“Under increasing federal control, access is being restricted. The health of the land is diminishing horribly. And the productivity is depressed,” Mr. Ivory said. “This is the only way to get better access, better health and better productivity.”