The owner of Rippon Lodge, one of the last standing Colonial-era tobacco plantations in Northern Virginia, is negotiating a sale of the Woodbridge property to Prince William County for eventual use as a museum or conference center.

The historic lodge, built in 1725 on the shores of the Potomac River, is Prince William's oldest house. Northern Virginia historians think it is the oldest property in the region, predating George Washington's estate at Mount Vernon by 32 years. Rippon has stayed in the same family for 275 years, since builder Richard Blackburn set out from the cathedral town of Rippon in Yorkshire, England, to make his fortune in the Colony of Virginia.

"It's a magnificent property that could be used for a whole host of passive things," said county Public Works Director Robert W. Wilson, whose office handles Prince William's land acquisitions.

Wilson said the county recently was approached by the property's current owner, Debra Jane Black, who lives in the District.

"She wanted to sell it, and she figured the county would be the one to buy and preserve it," Wilson said.

Black and county officials are negotiating a price for the estate, which overlooks Neabsco Creek and includes a 1,300-square-foot main house, carriage house and caretaker's cottage, cabin, barn and second small cottage on 40 acres near Route 1 and Blackburn Road in the county's eastern end.

The original property occupied more than 2,000 acres, but nearly all of that land has been sold off and developed.

The estate's assessed value was $514,000 last January, county records show. The county has applied for a $437,000 grant from the Virginia Land Conservation Foundation Fund to help pay for the property.

Rippon Lodge is unoccupied and is maintained by a full-time caretaker. If the sale goes through, Rippon would join Mount Vernon, Gunston Hall in Fairfax County, Oatlands Plantation in Loudoun County and a handful of other properties along the Potomac that were once tobacco- and wheat-farming estates and became open to the public.

Plans for a public use of Rippon Lodge so far are sketchy, and it's unclear where the county would find the money to restore and maintain the property and convert it to a museum, conference center or other use. But by shifting from private to public hands, the house could open a new door on Prince William's history.

"There's a huge potential for archaeological work at a site like this," said Nan Netherton, a historian of Northern Virginia who lives in Falls Church.

One project could be finding the plantation's slave quarters, which likely were destroyed after the Civil War. Unlike its neighbors on the Potomac, Rippon was not built a mansion but is instead a more modest 12-room, one-and-a-half story wood frame house. But it has a rich history and a lineage of prominent descendants.

Blackburn, the young colonist, was an architect and builder who designed the original Falls Church for which the Fairfax city is named and co-founded several towns, including Dumfries. He built Rippon in the Georgian style, with dormers and gabled stoops on each side. The house is featured in a watercolor sketch by the artist Benjamin Latrobe, who highlighted its site on a high knoll overlooking the Potomac, with a distant view of the Maryland shore.

Much of the house's beaded pine clapboard, oak timbers and fine woodwork are intact, as are its seven fireplaces. There's also a brick-lined tunnel leading from the cellar to a nearby ravine. The house, open to historical commissions only rarely, is filled with antiques and family portraits, war relics and Native American arrowheads, local historians say.

Washington is said to have visited Rippon on several occasions. Legend has it that two duels were fought in the house's drawing room, with one victim bleeding to death on the parlor floor. Blackburn died in 1757 at age 52, and the house has been owned by his descendants for all but a few years. One of the most prominent, Richard Blackburn Black, was a rear admiral in the Naval Reserve. He was an Antarctic explorer and lived in the house from 1952 until his death in 1992.

Black's daughter, Debra Black, the house's owner, could not be reached for comment.

Because it has changed hands only a few times, the house is in good condition, though those familiar with the property said it needs restoration work on its front wall and has termite damage.

"All in all, given its age, it's in excellent shape," Wilson said.