Center for American Progress

Expanding San Gabriel Mountains National Monument Would Increase Access to Protected Nature in Greater Los Angeles

Expanding San Gabriel Mountains National Monument Would Increase Access to Protected Nature in Greater Los Angeles

President Biden should utilize the Antiquities Act to expand San Gabriel Mountains National Monument to include 109,000 acres that are most proximal to nature-deprived communities.

The final full moon of 2020 rises over downtown Los Angeles with the San Gabriel Mountains in the background. (Getty/Asim Bharwani)

More than 18 million Californians reside within 90 miles of the pristine San Gabriel Mountains, which tower dramatically over the Los Angeles skyline. The mountains play an important role for the community, as they support one-third of Los Angeles’ freshwater resources. San Gabriel is home to threatened and endangered species, including 53 U.S. Forest Service sensitive plants and 300 California-endemic species, as well as more than 600 archaeological and historic sites. Due to the ecological and historic richness of the landscape, it serves as a vital educational resource for the local community.

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In 2014, President Barack Obama designated 346,177 acres of this southern California landscape, which span parts of the Bernardino and Angeles national forests, as San Gabriel Mountains National Monument to protect endangered species, cultural resources, outdoor recreation, and increase access to the outdoors for one of the largest urban centers in the country.

However, this designation did not include 109,000 acres of the Angeles National Forest closest to Los Angeles. A new Center for American Progress analysis, using new data from Conservation Science Partners (CSP), finds that expanding the monument to include this area would increase the number of people living within 5 miles by 90 percent.

U.S. Sen. Alex Padilla (D-CA) and U.S. Rep. Judy Chu (D-CA) have championed an effort backed by a coalition led by Nature for All, nearly 100 state and local elected leaders, and more than 100,000 community members to expand the national monument to include the 109,000 acres of public lands on the southwestern slope closest to the urban community. President Joe Biden, using executive action, should heed their call, which would advance his administration’s groundbreaking conservation progress toward conserving 30 percent of the nation’s lands and waters by 2030.

The case for expanding San Gabriel Mountains National Monument

Despite the wildlife and cultural resources of this landscape and the existing protections of San Gabriel Mountains National Monument, many residents of the Greater Los Angeles community—an area with high populations of historically marginalized and minority communities—still experience limited access to nearby protected nature. CAP’s analysis finds that expanding this national monument would increase the total number of people within 5 miles of the monument by 90 percent. This means that about 757,000 more people—more than 60 percent of whom are nonwhite—would gain greater access to nearby protected nature. The proposed expansion would benefit communities that have historically experienced inequitable access to nature, as well as positively affect ecosystems, clean water, and cultural preservation.

The Biden administration’s commitment to protecting access to nature

The Biden administration has demonstrated its commitment to protecting public lands through more than $18 billion in funding toward conservation projects and more than 26 million acres conserved in just three years. This historic, community-driven, and equity-centered conservation action is delivering progress on the president’s goal to protect 30 percent of U.S. lands and waters by 2030. Additionally, thus far, the Biden administration has safeguarded five landscapes across the country as national monuments. National monuments are a key conservation tool to protect lands with historic or scientific value. Some of the country’s most iconic public lands, such as Arches National Park and Olympic National Park, were originally protected as monuments under the Antiquities Act. The president has also coordinated a memorandum of understanding among 10 federal departments and agencies with the specific purpose of improving access to nature and investments in nature-deprived communities. President Biden should utilize the bipartisan and popular Antiquities Act to expand San Gabriel Mountains National Monument and increase access to nature for the Greater Los Angeles community.

The San Gabriel expansion is widely supported, including by the America the Beautiful for All Coalition, which represents more than 250 conservation and environmental justice nonprofits across the nation and has identified this expansion effort as one of its 2024 policy priorities, among other widely supported national monument campaigns. This proposal is also supported by President Rudy Ortega of the Fernandeño Tataviam Band of Mission Indians, a Native sovereign nation that represents 26 Tribal nations in present Los Angeles. Most recently, on November 7, 2023, the U.S. Forest Service hosted a public listening session on the proposed monument expansion, which drew hundreds of local community members to further voice support for the expanded protections.

Nature-deprived community analysis

To further assess how the San Gabriel Mountains National Monument expansion would improve access to nature for nearby communities, CAP and CSP assessed the local nature gap to find the degree to which nearby minority, low-income, and nature-deprived communities would benefit from the proposed expansion. Nature-deprived communities are defined as those that experience higher rates of nature loss than the state average. The nature gap is the uneven and inequitable distribution of natural areas among communities of color and low-income communities, driven by historical discrimination, dispossession, and exclusion on public lands.

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To evaluate how the proposed expansion would improve access to nature, this analysis compared the current boundaries of the monument to the proposed expansion boundaries in order to determine how many more people of different communities would be within a closer proximity to protected nature if the site were expanded. The analysis determined that there would be a 90 percent increase in the total number of people within 5 miles of the national monument’s expanded boundary compared with the current boundary. As a result, 757,000 more people would be within 5 miles of San Gabriel Mountains National Monument, including nearly 464,000 more nonwhite residents. Black, Latino, and Asian Americans historically experience the most severe nature gap across the country. In the Los Angeles area, almost half of the population identifies as Latino. The monument expansion would help locally deliver on the president’s commitment to promote equitable access to nature in nature-deprived communities.

Expanding this national monument would increase the total number of people within 5 miles of the monument by 90 percent.  

Driving time analysis

The analysis took an additional approach to determine how the San Gabriel Mountains National Monument expansion would increase access to nature by estimating how the driving time for local communities to the site would change if the national monument’s boundaries were expanded. The expansion would result in a nearly 20 percent reduction in driving time to access the protected site for all residents within 30 miles. Notably, driving times would be significantly reduced—from more than one hour to nearly 30 minutes—for communities that are jointly nonwhite, low income, and nature deprived. In the Greater Los Angeles community, areas with higher proportions of nonwhite residents would see a 26 percent reduction in driving time to the monument.

Racial and income disparities exist in car ownership across the country, and long driving times to protected nature are a known inhibitor to visitation of public lands. The significance of these disparities increases with the consideration that nearby protected nature has measurable, positive physical and mental health impacts. Communities of color across the country experience higher rates of chronic illness and disease due to long-term impacts of systemic racism. The public health benefits of having access to nearby protected nature in urban hubs such as Los Angeles that have high populations of nonwhite communities cannot be understated. The Biden administration has shown a direct and meaningful focus on channeling investments toward environmental justice and addressing protected nature as a civil rights issue. The San Gabriel Mountains National Monument expansion is one more way that President Biden can further his environmental justice commitments.


The Biden administration has made a clear commitment to conservation during its first three years in office, including designating five new national monuments across the country. This historic pace of conservation has rarely been seen before, but at a time when communities are experiencing some of the most prevalent and damaging impacts of climate change, the administration must continue to use every tool at its disposal to preserve locally cherished, culturally important, and ecologically rich landscapes for the clean air, clean water, and access benefits to communities. Expanding the boundaries of San Gabriel Mountains National Monument to include 109,000 acres closest to Los Angeles would significantly improve access to nature for one of the country’s largest, most diverse cities. This expansion would further deliver on President Biden’s goals and demonstrate how executive action can prioritize community needs and the future of the planet in a changing climate.

The author would like to thank Nicole Gentile, Jenny Rowland-Shea, Drew McConville, Christian Rodriguez, Beatrice Aronson, Bill Rapp, Patrick Freeman, Justin Suraci, Elissa Olimpi, Conservation Science Partners, Daniel Rossman, and the local and national conservation leaders who are building impactful and equitable conservation solutions every day.


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Sam Zeno

Policy Analyst, Conservation Policy


Conservation Policy

We work to protect our lands, waters, ocean, and wildlife to address the linked climate and biodiversity crises. This work helps to ensure that all people can access and benefit from nature and that conservation and climate investments build a resilient, just, and inclusive economy.

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