James Monroe’s Oak Hill estate has historic roots. Some hope to preserve it as a Virginia park.

ALDIE, Va. — The room where President James Monroe crafted part of his famed doctrine exudes a quiet, stately atmosphere.

Inside the enclosed west porch a few footsteps away, a quarried-stone floor marked by fossilized dinosaur tracks glimmers in the sunlight. Just around the corner, a portico built by enslaved African Americans looks out over rolling foothills stretching into the misty northern Virginia horizon, a captivating view untarnished by monied property developments bellying up nearby.

It’s an early morning at Oak Hill, where centuries of history are deeply rooted in Monroe’s Loudoun County estate. It’s the last home of a presidential Founding Father still in private hands, according to conservation experts.

That is, maybe, until now.

The DeLashmutt family, which has owned Oak Hill in the community of Aldie since 1948, hopes to convert its sprawling 1,240 acres (502 hectares) into a state park. A bill to that effect unanimously passed the House of Delegates last month but failed in the Senate.

The DeLashmutts, along with a nonprofit corporation, the Conservation Fund, hope Republican Gov. Glenn Youngkin will revive the multimillion-dollar project by including it in his proposed amendment to the budget bill ahead of the General Assembly’s veto session. The governor has until Monday to submit his revisions.

‘‘We’ve taken good care of it,‘’ family matriarch Gayle DeLashmutt said, gazing up at trees in the garden during a recent tour of the grounds. ‘’And I think it’s time to let somebody else do it.‘’

The DeLashmutt family, which is unrelated to the Monroes, is part of a long line of Virginians who have lived in Oak Hill. Other Founding Fathers' homes in the state — Thomas Jefferson’s Monticello, George Washington’s Mount Vernon and Monroe’s Highland estate — are owned by educational and historical institutions that open the estates' doors to the public.

The residence at Oak Hill has a complex heritage: At the top of a split staircase leading to the entrance sits a gifted bell from the decommissioned USS Oak Hill. Inside, elegant parlors feature fireplace mantelpieces made of decadent marble, a gift from Monroe’s longtime friend, the Marquis de LaFayette, to thank first lady Elizabeth Kortright Monroe for saving his wife from the guillotine. On an interior windowpane, a young man with the last name of Fairfax, a family that previously owned the house, scratched his name and the date of his graduation from the Virginia Military Institute.

Gayle DeLashmutt’s daughter, India DeLashmutt, grew up on the estate, charging about on go-carts and sledding down steep hills in the same place that Monroe hosted first lady Dolley Madison more than 100 years earlier. Her father used to tell her stories about finding arrowheads in Little River, a tributary that streams through the property.

‘‘There’s just this span of time, and this place can really represent it,‘’ she said.

The estate also embodies the histories of the enslaved African Americans who built and cared for the property.

There is George Williams, an enslaved carpenter who constructed the main house in Oak Hill, according to independent researcher Emily Stanfill. And Natus Berryman, who lived at Oak Hill before being forced to move to the South, said Lori Kimball, another researcher.

Opening the estate to the public full time would allow people to learn more about their stories, Kimball said.

Donna Bohanan, chair of the Black History Committee at a Loudon County genealogical library, said it would also educate the public about the Indigenous people and tenant farmers who lived on and worked the land.

‘‘I advocate for not just focusing on the great men of history or military history because that leaves out a lot,‘’ Bohanan said. ‘’By telling our more inclusive stories, we can start to see the connections between all of us as members of the human race.‘’

Loudoun County has allocated $22 million toward the roughly $52 million needed to support the project, while the Conservation Fund and other groups have raised another nearly $25 million. The family is selling the property for $20 million. The Conservation Fund says the state won’t have to pay a dime toward the project.

The legislation for such an acquisition, backed by Democratic Del. Alfonso Lopez, passed unanimously in the Virginia House last month but stalled in the state Senate. During the final days of the session, Democratic Sen. L. Louise Lucas told reporters that she thought the bill was an excellent idea but expressed concern about long-term commitments from the state, even if it has no upfront financial obligation.

‘‘That’s a lot of park for somebody to take care of," she said. “Those are the kinds of things you have to consider when you’re working on these budgets.‘’

Youngkin said Wednesday he was initially resistant to the project because he was not sure the business plan was fully fleshed out. But he said he felt less uneasy after touring the estate with Republican Del. Geary Higgins, whose district includes Oak Hill.

‘‘We had a good visit, and I’m still trying to decide what we do,‘’ Youngkin said. ‘’No promises, but I’m open-minded.‘’

Olivia Diaz is a corps member for the Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.