The Department of Interior (DOI) said it will review 27 national monument designations in order to comply with two executive orders (EO) signed last month by President Trump, and will seek public comments over the designations — a first in the department’s history.

Federal law — specifically, the Antiquities Act of 1906 — gives the president the authority to designate national monuments from federal lands, essentially removing them from future oil and natural gas development. But on April 26, Trump signed an EO ordering DOI to review any designation of more than 100,000 acres made since Jan. 1, 1996, arguing that previous administrations abused the law and sometimes made designations against the will of the local public.

In a statement last Friday, the department said that while “a public comment period is not required for monument designations under the Antiquities Act; however, DOI Secretary Ryan Zinke and President Trump both strongly believe that local input is a critical component of federal land management.” DOI added that it would soon publish a notice in the Federal Registerofficially opening the public comment period, and would begin accepting comments online after May 12.

The department added that written comments related to the Bears Ears National Monument, located in southeast Utah, must be submitted within 15 days of the published notice in the Federal Register. Written comments related to the other 26 monuments are due within 60 days of the notice’s publication.

“The DOI is the steward of America’s greatest treasures and the manager of one-fifth of our land,” Zinke said. “Part of being a good steward is being a good neighbor and listening to the American people who we represent. Today’s action, initiating a formal public comment process finally gives a voice to local communities and states when it comes to Antiquities Act monument designations.”

Zinke added “there is no pre-determined outcome on any monument.” The comment echoed a similar statement he made just before Trump signed the EO, when he said the order “does not remove any monuments [or] weaken any environmental protections on any public lands.” But language contained in the EO strongly suggests the Trump administration may try to trim the size of some monuments.

Twenty-two of the 27 national monuments up for review, including Bears Ears, are in the onshore, and all but one — Maine’s Katahdin Woods and Waters — are in the West. The remaining five are marine monuments in the offshore.

Bears Ears, located in San Juan County, UT, appears to be the most controversial designation. President Obama set aside 1.35 million acres for the monument last December, shortly before leaving office. The area has seen mostly conventional but also some unconventional oil and gas drilling. San Juan County also overlays the Paradox Basin, which includes the Cane Creek and Hovenweep shales.

The largest onshore monument under review, totaling 1.7 million acres, is the Grand Staircase-Escalante National Monument in Utah. The Mojave Trails National Monument in California is second at 1.6 million acres, while the Grand Canyon-Parashant National Monument in Arizona is fourth at 1.01 million acres.

The DOI will review the San Gabriel Mountains National Monument (346,177 acres) in California and four others in the state: Berryessa Snow Mountain (330,780), Giant Sequoia (327,760), Carrizo Plain (204,107) and Sand to Snow (154,000). In Arizona, the department will review Sonoran Desert (486,149), Vermilion Cliffs (279,568) and Ironwood Forest (128,917).

Two monuments in Nevada, Basin and Range (703,585 acres) and Gold Butte (296,937), will also be reviewed, as will two monuments in New Mexico, Organ Mountains-Desert Peaks (496,330) and Rio Grande del Norte (242,555).

Colorado’s Canyons of the Ancients National Monument (175,160 acres) will also be reviewed, as will Oregon’s Cascade Siskiyou (100,000), Idaho’s Craters of the Moon (737,525), Washington’s Hanford Reach (194,451) and Montana’s Upper Missouri River Breaks (377,346).

The DOI said a review of Katahdin Woods and Waters was being performed “to determine whether the designation or expansion was made without adequate public outreach and coordination with relevant stakeholders.” The area includes 87,563 acres in Maine.

A separate EO signed by Trump on April 28 calls for the secretary of the Department of Commerce — in consultation with Zinke and the secretaries of the Defense and Homeland Security departments — to review any marine national monuments designated or expanded within the last 10 years.

The five marine national monuments under review are Papahanaumokuakea (89.6 million acres) in the Pacific Ocean, off the coast of Hawaii; Marianas Trench (60.9 million) in the Pacific, off the coast of the Commonwealth of the Northern Mariana Islands; Pacific Remote Islands (55.6 million) in the Pacific; Rose Atoll (8.6 million) in the Pacific, off the coast of American Samoa; and Northeast Canyons and Seamounts (3.1 million) in the Atlantic Ocean.