President-elect Joe Biden will nominate a Native American to serve as his interior secretary, leading the agency governing public lands, US media say.
If confirmed, Congresswoman Deb Haaland will be the first indigenous person to lead the department, which also plays a key role in Native American affairs.
She will also be the first Native American in a cabinet secretary role.
Native rights groups and progressive Democrats had pushed for the New Mexico lawmaker's nomination in recent weeks.
"It would be an honour to move the Biden-Harris climate agenda forward, help repair the government to government relationship with Tribes that the Trump Administration has ruined, and serve as the first Native American cabinet secretary in our nation's history," Ms Haaland said in a statement quoted in the New York Times.
Ms Haaland, 60, is a member of the Laguna Pueblo tribe and made history as one of the first two Native American women ever elected to Congress in 2018.
Speaker of the House of Representatives Democrat Nancy Pelosi described Ms Haaland as one of the most respected members of Congress.
Fellow progressive Democratic Congresswoman Alexandria Ocasio-Cortez praised her nomination as "historic on multiple levels".
"She brings a commitment to climate and justice to the position, and the historic weight of having a Native woman, no less a progressive one, in charge of federal lands is enormous."
As secretary of the interior, Ms Haaland would play a key role in implementing the administration's environmental policies. These include a promise to move the federal government away from fossil fuels. Ms Haaland's state of New Mexico is a part of the US Climate Alliance and has already set its own bold climate goals.
Ms Haaland also comes with two years of experience on the House Natural Resources Committee.
In all, she would oversee 500 million acres of federal lands, 62 national parks and work with 1.9 million Indigenous Americans from 574 federally recognised tribes. The interior secretary also manages the Bureau of Trust Funds Administration, which handles Native American finances, and Bureau of Indian Education.
Her appointment would also have real cultural significance, as the interior department has historically clashed with Native American groups. For instance, many of the nation's national parks, like Yellowstone, were cut out of Indigenous land by the US government.
More than 120 tribal leaders joined a petition from the Lakota People's Law Action Center to back Ms Haaland. In addition, celebrities and environmental activists also called for the president-elect to choose her.
A Change.org petition for Ms Haaland's selection received nearly 40,000 signatures ahead of Thursday's news.
Ms Haaland's nomination means that the Democratic majority in the lower chamber of Congress has become even slimmer - just three seats until replacements for Ms Haaland and other cabinet appointees are elected.
'I see myself when I see Deb'
We asked Native Americans about what they thought of Ms Haaland's historic nomination.
Dr Twyla Baker, 44, from North Dakota, is a citizen of the Mandan, Hidatsa, and Arikara Nation and president of the tribally chartered college of these three affiliated tribes.
How do you feel?
I see myself when I see Deb. The things that are important to me - tribal colleges, Indian Education, etc. - are important to her and I've seen her demonstrate that, speak about it and advocate for it. It's amazing. I'm still in shock.
My three affiliated tribes actually have a vested interest because we are in court with the Department of Interior right now fighting for our land rights. So her being appointed as secretary is welcome news and I'm hoping we will see a voice of reason and our land rights restored.
Why does this matter so much now?
We have lost so much ground and have stepped back with these last administrations in terms of protecting our lands and our resources.
To have a breakthrough like this is a really big deal. It's going to be amazing to have my daughters - and my son - see somebody like Deb in a position of this magnitude.
Jordan Daniel, 32, from South Dakota, is a Lakota woman and a Los Angeles-based activist who runs a nonprofit to elevate indigenous voices.
How do you feel?
It means so much to me and it has meant so much to Indian country so far just seeing the response on social media.
People that are non-native will be able to see firsthand some of the hardships that we have to deal with, but also our resiliency.
All the credit needs to go to organisers. We're showing up, putting our foot down and saying enough is enough, we deserve better.
Why does this matter so much now?
We are constantly having to speak out against the injustice our communities are constantly facing. And this is giving us a seat at the table - to make sure indigenous rights can be valued, to show what indigenous sovereignty looks like and to build a better future moving forward.
Congresswoman Haaland made sure that Native people weren't left out of the Covid relief packages. Twice. So, having this voice, impact and influence on a national scale is going to do so much good for our communities but also for our next generation.
Reporting by Sam Cabral