It was an executive order that made waves in environmental circles: after only a week in office, President Joe Biden pledged to preserve 30% of US lands and waters by 2030.

The so-called 30 by 30 conservation goal has already met with bipartisan support in Congress, and it aligns with science-based global preservation targets to reach an eventual target of 50% by 2050.

So which US areas might be at the top of the list? Environmentalists have a few ideas.

The US Geological Survey reports that only 12% of US lands are permanently protected, with roughly 23% of its coastal waters protected. That means that in order to reach Biden’s goals, the country will have to conserve more than 400m acres land and inland waterways alone in the next 10 years.

Restoring national monuments such as Bears Ears and Grand Staircase-Escalante, where Trump slashed protections in 2017, is a likely first step – it’s “the low-hanging fruit”, according to Aaron Weiss, deputy director of the Center for Western Priorities.

Bears Ears national monument was reduced by the Trump administration by a combined 2m acres.
Bears Ears national monument was reduced by the Trump administration by a combined 2m acres. Photograph: The Washington Post/Getty Images

As for the next moves, “I think to make this work durable and lasting over time, this work has to come from the ground … we should start where agreement [already] exists,” said Tracy Stone-Manning, associate vice-president for public lands at the National Wildlife Federation.

She counted off a slew of locally driven initiatives primed to expand conservation areas, including 80,000 acres of big sky country in Montana and 1.3m acres of Mojave desert, and bighorn sheep habitat, in Nevada. A proposal on the cards in California could save 250,000 acres of river rapids and redwood groves. And a recently reintroduced act in Colorado would protect over 400,000 acres of craggy mountains and key migration corridors.

Conservationists also anticipate the return of locally based national monument campaigns to preserve red-rock gorges and rolling hills in Oregon’s Owyhee Canyonlands, as well as towering rock formations and ancient cliff dwellings in Arizona’s Greater Grand Canyon.

A majestic redwood in Roosevelt Grove at Humboldt Redwoods state park in California.
A majestic redwood in Roosevelt Grove at Humboldt Redwoods state park in California. Photograph: Danita Delimont/Getty Images/Gallo Images

But even that incremental acreage, Weiss says, won’t get the country to 30 by 30 alone – “not even close”.

Millions of acres of additional protected landscapes will need to emerge in the next 10 years. At the top of conservationists’ lists are areas rich in biodiversity: mountain ranges like the Appalachians and the Blue Ridge Mountains, wide swaths of prairieland across the Great Plains, old-growth forests in the Pacific north-west, and currently under-protected coastal forests in the American south-east.

Some of these regions, like the Cumberland Forest in Virginia, Kentucky and Tennessee, are already the subject of preservation efforts. Others are previously acquired lands by conservation groups, like Lake Wimico, a freshwater wetland refuge for resident and migratory wildlife in Florida, or scattered parcels of forested land in the west. And still others, mainly in the south-east, are held by private landowners, making voluntary protection agreements – commonly called conservation easements – a key strategy.

An abandoned mine wastewater pond high in the San Juan mountains in southwestern Colorado.
An abandoned mine wastewater pond high in the San Juan mountains in south-western Colorado. Photograph: Brennan Linsley/AP

Although environmentalists will likely encourage Biden to meet his goals by utilizing the Antiquities Act, which allows presidents to set aside nationally significant lands and waters for permanent protection, they say local efforts pushing protections for a given area will be essential.

“One of the real exciting opportunities for [30 by 30] is that it’s really not a top-down mandate, where someone in DC is drawing the map and getting us towards 30%,” said Sierra Club lands, water and wildlife director Dan Ritzman. “The idea is really locally driven conservation efforts – these are bottom-up campaigns, where people familiar with the land and affected by its management will be deeply involved in its conservation.”

This may also require rethinking traditional definitions of conservation, which have often equated protection with human absence, and largely ignored or excluded indigenous communities’ ways of life and ties to sacred land. But Woody Lee, member of the Navajo Nation and executive director of indigenous-led organization Utah Diné Bikéyah, says Bears Ears national monument — which is directly co-managed by sovereign tribal nations and the US federal government — could serve as a model.

“I think [Bears Ears] blazed a trail … this particular type of initiative has never been done,” Lee said. “I would support other tribes that want to go the same path, or a similar path that would have the same result.”

Granite and Silver Peaks in Mojave national preserve in California.
Granite and Silver Peaks in Mojave national preserve in California. Photograph: Posnov/Getty Images

Even if some protected areas are still privately owned, “ownership isn’t as important as outcome,” said Tom Cors, government relations director of lands for the Nature Conservancy, which has used approaches like acquiring land itself or obtaining easements on private lands in order to protect an area.

Cors calls the 30 by 30 goal a “10-year moonshot” precisely because it demands federal and state government work alongside local stakeholders, including private farmers and ranchers, urban communities and sovereign tribal nations. In other words, it will require a tremendous amount of collaboration at an unprecedented scale and speed.

The good news is that, according to the recent Conservation in the West survey, which polls rural and urban western voters across the political spectrum, 77% supported 30 by 30 targets. And many favored limiting resource extraction on public lands.

By summer, it is likely that the interior department and other US agencies will have developed a roadmap to reach the 30 by 30 goals. That means there is still time for Americans to influence the process.

“There is no secret list [of lands for conservation]; I wish there was,” said Stone-Manning.

“We need to put a call out to America: send us your ideas. Let’s hear from the people who know their places best.”