Yes, George Washington slept here. But so did Liz Butler, and that was much more important to Robin Richardson Greenhalgh. Growing up in this stately stone farmhouse near Berryville, Va., Greenhalgh's slumber parties with her third-grade friends were a bigger deal to her than the sleepovers of a Founding Father.

"To me, it was just our house," said Greenhalgh, 54, looking around the spacious entry hall of Fairfield, her family's home for seven generations. It is remarkably well preserved after welcoming visitors, both grand and giggling, for longer than this country has been a country. "I really didn't appreciate its remarkable heritage until much later."

But now that Greenhalgh fully celebrates the heritage of a house that was built by George Washington's first cousin and later owned by Robert E. Lee's aunt, she is preparing to say goodbye to the Clarke County estate. Citing the time and cost of maintaining a colonial mansion, Greenhalgh has put Fairfield on the market - even though that leaves her, and preservationists, anxious about the fate of one of Virginia's great unsung historic estates.

"It is probably one of the most significant colonial homes in the state, both in pedigree and architectural detail," said David Boyce, executive director of Long Branch Historic House and Farm, an 18th-century manor in nearby Millwood. "Here is a home that can boast of not only of having George Washington spend the night, but Martha, too. And multiple times."

Greenhalgh, a real estate broker, has listed the house and 38 acres for $3.9 million, an elite category where it can take years to find a buyer. To make the sale even more complex, Greenhalgh and her husband, George, plan to add covenants to the deed to restrict changes that future owners can make to the house and land. No condos, she said; no cutting up the farm for McMansions. A wealthy, history-minded family would be ideal, she said, or a college.

"With the house built by the Washington family and the second owners being the Lee family, I can think of one perfect university," Greenhalgh said.

Washington and Lee University in Lexington has not expressed any interest.

Whenever Greenhalgh passes the graveyard of the local Episcopal church, she feels the weight of the many Richardsons who have lived in the house since her great-great-great grandfather bought it 31 years before the Civil War.

Three years ago, after she and her sister inherited the property from their mother, Greenhalgh bought out her sister's share to stave off the inevitable. "I wasn't ready" to sell, she said.

But now that the Greenhalghs' daughters are in their 20s, the couple finds that an 8,400-square-foot stone mansion with what used to be smokehouses and slave cabins scattered around the yard does not make an ideal empty nest. Recent roof repairs ran more than $80,000. Restoring dormer windows in the attic costs $1,200 a piece.

"There's so much we'd like to do here, but we just don't have the means," Greenhalgh says as she looks around a kitchen with a fireplace big enough to serve as a bedroom. "I think my ancestors would understand that the time has come."

On a crisp January day, Greenhalgh showed off the house. Part Realtor, part docent, she pointed out the family initials meticulously carved into the stones and colonial-era graffiti left by Washingtons and Armisteads.

The place was built in 1770 by a busy planter named Warner Washington, whose cousin George and his family were frequent guests. In his letters, the first president mentions Warner, a fox-hunting buddy, and his stays at Fairfield.

In 1809, the sister of Henry Lee III - the Revolutionary War hero known as "Light Horse Harry," and the father of Robert E. Lee - bought the place.

That lineage has attracted interest for decades. Greenhalgh remembers her parents and aunts, who lived in different wings of the house, giving impromptu tours to visitors and scholars who would show up unannounced. Plaques by the front door honor the house's place on the National Register of Historic Places and Virginia's list of historic landmarks.

Architects have drawn a link between Fairfield and Kenmore, the home of George Washington's sister Betty, near Fredericksburg. The central layouts of the two houses are identical, and both may have been designed by noted colonial architect John Arlis. Arlis, in fact, asked to be buried at Fairfield, and Greenhalgh remembers her father showing her a clutch of ancient graves, now lost.

"It is a very good Georgian house," said Ed Chappell, director of architectural research at Colonial Williamsburg, who wrote a study of Fairfield in 2009. "In addition to its sort of blue-ribbon history, it is one of the late colonial Virginia houses that survived in very good shape."

Many grand old houses didn't survive a rash of remodeling in the early 20th century that turned historic properties into modern estates, Chappell said. He cited James Madison's Montpelier, which just completed a $25 million restoration to its original state.

George Greenhalgh pulled out a sheaf of yellowed blueprints to show what could have gone awry at Fairfield - a series of proposed changes through the decades, from massive colonnades to high Victorian domes.

"We dodged a bullet," George said.

"Thank goodness," Robin said.

The house, often studied, continues to reveal surprises. In an old magazine article about Fairfield, Greenhalgh was astonished to find a reference to a "master's retreat" and a fuzzy photograph of a huge room with a vaulted wood ceiling. A mighty elk head loomed over the fireplace. News to the family. It turned out the "retreat" was an early iteration of their own living room; they found the wood paneling, intact, above their ceiling. Future owners may want to restore that room, she said.

Two and a half centuries of private control have kept Fairfield intact, Boyce said. He and other historians hope the next owner will keep up the tradition.

Boyce knows firsthand the constant challenge of running a farm that predates the steam engine. "I have a staff and an endowment, and it's still daunting," he said. "One hopes that the buyers of Fairfield will know what they are getting into and have an appreciation for it. You're buying a way of life. It's going to take someone special."