A plan to create a massive national monument adjacent to Joshua Tree National Park received a formal proposal this week, with advocates hoping the official designation would preserve habitats for endangered species and important tribal cultural sites on the land.

U.S. Rep Raul Raiz, a Democrat representing California’s 25th congressional district, submitted the formal proposal, which was first announced by a coalition of environmental groups last year, the Desert Sun reported.

California’s 25th congressional district includes Imperial County, the Eastern Coachella Valley and the cities of Banning, Beaumont, Blythe, Hemet, Needles and San Jacinto.

The site would span about 660,000 acres and sit alongside the southern border of Joshua Tree National Park. The proposed plan would include land in both Riverside and Imperial counties.

The proposed site for the monument, known as Chuckwalla National Monument, would include the popular Ladder Canyon and Painted Canyon Trail, where hikers can see the giant colorful rock formations and climb up ladders through the narrow canyon, the Sun reported.

In addition to the new national monument proposal, another proposal would expand Joshua Tree National Park by about 17,000 acres east toward the Eagle Mountain area.

The national monument proposal could be approved by Congress or a presidential designation under the Antiquities Act. Ruiz has already initiated the congressional process earlier this month when he introduced the Chuckwalla National Monument Establishment and Joshua Tree National Park Expansion Act of 2023.

The proposal also has the support of local organizations, elected officials and tribes who have expressed their interest in the project with the “Protect Chuckwalla National Monument” campaign.

However, not everyone is on board; a petition on Change.org urges residents to oppose the proposed changes.