WASHINGTON — President Obama designated two new national monuments on Wednesday, protecting 1.35 million acres of federal land surrounding the Bears Ears Buttes in southeastern Utah and about 300,000 acres around Gold Butte in Nevada, northeast of Las Vegas.
The monuments are Mr. Obama’s latest effort to protect public lands and waters from development and to nail down as much of his environmental legacy as he can before Donald J. Trump assumes the presidency on Jan. 20.
The new desert monuments, designated under the executive authority of the 1906 Antiquities Act, encompass Native American sites of sacred and archaeological importance, as well as wildlife habitats and hiking and hunting terrain.
Efforts to place the Bears Ears Buttes under federal protection have been underway since 1936, when President Franklin D. Roosevelt’s interior secretary, Harold L. Ickes, proposed the monument designation. Native American tribes began promoting legislation to protect Gold Butte in 2008.
“Today’s actions will help protect this cultural legacy and will ensure that future generations are able to enjoy and appreciate these scenic and historic landscapes,” Mr. Obama said in a statement.
But some local residents and elected officials have opposed the Obama administration’s extensive efforts to protect Western landscapes, calling them federal land grabs. The family of a Nevada rancher, Cliven Bundy, helped take over a national wildlife refuge this year in protest against such federal actions.
While Mr. Trump has vowed to undo the Obama-era environmental agenda, White House officials said they did not believe he would have the authority to reverse Mr. Obama’s park, monument and wilderness designations under the 1906 law. No president has undone a predecessor’s designations in the law’s 110-year history.
“The Antiquities Act gives the authority to create monuments and does not give explicit authority to undo them,” said Christy Goldfuss, the managing director of the White House Council on Environmental Quality.
However, after Mr. Obama this month used an obscure provision of a 1953 law to place about 115 million acres in the Arctic Ocean and about 3.8 million acres of the Atlantic Ocean permanently off-limits to drilling, opponents, including oil companies, said they intended to file a legal challenge.
Native American groups and environmentalists hailed Mr. Obama’s moves Wednesday in Nevada and Utah.
“This is an exciting day for Navajo Nation,” Russell Begaye, the tribe’s president, said in a phone call with reporters.
“We have always looked to Bears Ears as a place of refuge, as a place where we can gather herbs and plants and as a place of sacredness,” he said. “It is a place of safety and fortitude. It is a place where our ancestors hid and survived from U.S. cavalry during the Long War.”