Less than a mile north of McClellanville, 785 acres of pine forest merge with saltwater, a prime location for an exclusive new subdivision or golf course development.

The owners of this land, the DuPre family, could have cashed in someday. But a DuPre has owned or managed this property for the last 300 years -- 10 generations.

Thanks to these deep roots, the county's greenbelt program and The Nature Conservancy, the family decided to forever protect the land with a conservation easement, representatives from the family and The Nature Conservancy said Monday.

"It's a special place," said John DuPre, a forester and part-owner.

It's special because of its size, location and history, he and others said. Locally, the tract is known as Palmetto Plantation, named because the family home was built between two palmettos.

At 785 acres, it's 142 acres larger than James Island County Park. The tract sits along a full mile of the Intracoastal Waterway. Lighthouse Island and Cape Romain National Wildlife Refuge are on one side, and Francis Marion National Forest is on the other.

"It makes a seamless connection from the uplands to the marsh, and there aren't many places like that left," DuPre said.

That's because the construction of Francis Marion National Forest remains somewhat unfinished.

On maps, the national forest and refuge look like solid blocks of green. But they're also filled with "in-holdings," land still owned by private owners.

A large number of in-holdings are located between the refuge and national forest, parallel to U.S. Highway 17. Palmetto Plantation is in this corridor.

Elsewhere in this corridor, especially in Awendaw, developers have floated plans to build hundreds of homes.

"There's a strong conservation ethic up here," said DuPre, a naturalist who sometimes guides kayak trips through the national forest.

"There was a lot of discussion in the family (about selling to developers) and a lot of back and forth, but in the end, we agreed we didn't want to see the place turned into a housing development, which is almost certainly what would have happened."

The Charleston County Greenbelt Program, which is funded with a half-cent sales tax, awarded a $921,000 grant to The Nature Conservancy to buy the easement from the DuPre family. The easement's true value was more than $3 million.

"We were extremely pleased to participate in the protection of this significant property," said Hugh Lane, chairman of the greenbelt board.

The family's roots there stretch back to 1710, when Josias DuPre bought the land. The Dupres lived there until the last years of the Great Depression, when Helen Laval DuPre sold to George McCullough Miller and Flora Whitney Miller, a wealthy couple from New York.

Andrew H. DuPre, former manager of Cape Romain Wildlife Refuge, managed the property for the Millers, who used it as a duck hunting preserve. Family lore has it that the Millers were busy with their lives in New York, including the expansion of the Whitney Museum, and offered to return the land to DuPre because they knew he loved it so much.

Other accounts maintain that DuPre asked to buy it back, said Katharine DuPre Walton, who is compiling a history of the DuPre family.

In the end, Andrew Dupre brought Palmetto Plantation back into the family's hands. He died in 1979 on the steps of the house at Palmetto, a few feet from where he was born, Walton said.

DuPre's widow, Katharine Morrison DuPre, conveyed the property to Anthony DuPre, John DuPre, Kay DuPre Boggs, Alice DuPre Jordan and William DuPre.

"Their contribution will ensure the protection of the natural integrity of this area in perpetuity," said Ashley Demosthenes, associate director of land protection for The Nature Conservancy's South Carolina chapter.