With the purchase of a 54-acre property — including two historic buildings — researchers and archaeologists at Oatlands Historic House and Gardens in Leesburg will soon have new territory to explore.

The board of Oatlands, a National Trust Historic Site, announced last week that it had purchased the adjacent parcel, known as Oatlands Hamlet, which was once part of the original 3,400-acre estate. In the early 1800s, the property was a sprawling wheat plantation owned by George Carter, a descendant of one of Virginia’s first families, and tended by more than 100 slaves. More than 260 acres of the original estate was donated to the National Trust for Historic Preservation in 1965.

Since then, the restoration and archaeological exploration of the property has made Oatlands a popular site for educational programs, community festivities and other public and private events — all functions that will be improved by the addition of the newly purchased hamlet, said Andrea McGimsey, executive director of Oatlands.

“This is going to have a beneficial impact on everything we do,” McGimsey said. “We’re still in the very early days of planning how we can use the land . . . this was a truly unique opportunity that we really couldn’t pass up.”

The new parcel had a price tag of $1.85 million. Oatlands announced that it will launch a campaign to raise $2.5 million over the next two years, money that will also cover repairs and maintenance on the property. Because the site does not receive federal funding, McGimsey said, the campaign will focus on benefit events, gifts from foundations and other organizations, and community support.

Oatlands Hamlet is the first major addition to the site in more than a decade. In 2002, the board launched a high-priority fundraising campaign to purchase 68 adjacent acres known as the Smith Preserve, a parcel that would otherwise have been sold to a developer.

As historians and archaeologists continue to piece together the estate’s past, a photograph from the 1930s — hanging in the Oatlands gardener’s office — offers a clue: An orchard grew on the Oatlands Hamlet land, south of the estate’s Greek revival mansion and opposite a stately walled garden.

“You can see how this property was part of the historic core of the estate,” McGimsey said.

The hamlet also includes a massive evergreen tree known as a blue atlas cedar, a defining presence on the estate. Two others stand outside the property’s mansion and carriage house.

“They were a triumvirate, planted at the time when the property was all one estate,” McGimsey said. “Just to reunite those three trees is amazing.”

Two historic stone buildings sit on the new parcel: a stone house, believed to have been a dairy, and another home called the Emmet House, after the family that formerly owned Oatlands Hamlet, McGimsey said. The property was purchased from descendants of the family who recently put the land up for sale, she added.

The second stone house on the property contains a mural of the former Oatlands estate painted across the dining room walls, a find that especially thrilled the Oatlands board members and staff, McGimsey said.

As Oatlands begins to incorporate its new land into the existing site — foliage along the property lines will be “cleaned up, to open the flow of the property,” McGimsey said — the possibilities for further historical exploration abound. The Loudoun Archaeological Foundation is particularly interested in the possibility of Native American artifacts on the new property, she said.

“We’re so excited to do archaeology there,” she said. “This is going to be less disturbed ground, and we’re excited to see what we find there.”

For years, archaeologists have also hunted for evidence of the former slave quarters on the property, so far without success. They plan to continue their search on the new land, McGimsey said.

“We’re actively looking for that,” she said. “We’re working hard to interpret our African American past, and all of the diverse stories of Oatlands.”