For the first time in a generation, Montgomery County's sprawling Erdenheim Farm has changed hands.

In a 10-way, multimillion-dollar deal that permanently restricts development on 426 acres of the treasured land, most of the former gentleman's farm inherited by the late F. Eugene "Fitz" Dixon Jr. became the property yesterday of a preservation foundation and a Radnor executive.

And it will remain a vast, cattle-and-sheep-populated farm improbably perched on the bustling border between Philadelphia and its suburbs.

"We wondered how in the world we're ever going to get this thing done," said Hugh G. Moulton, chairman of the Whitemarsh Foundation, which has worked since 2001 toward Erdenheim Farm's preservation. "Finally, all of the pieces have fallen into place."

The transaction leaves just 14 acres of Erdenheim Farm in the hands of the Dixon family, whose relations have owned its rolling pastures since Dixon's uncle George D. Widener Jr. purchased the property in 1912.

Erdenheim Farm has been lush farmland for centuries under a succession of prosperous owners reaching back to William Penn. Over the last century, as suburbs spread around it, Erdenheim Farm remained an island of countryside where the region's children could glimpse Black Angus cattle and Border Cheviot sheep, which graze the land today.

Dixon inherited the land on Widener's death in 1971 and farmed it for 35 years, holding onto nearly the entire property despite repeated offers from land developers. When he finally sold off a tract of about 50 acres in 2001 for a retirement community, the transaction led to the Whitemarsh Foundation's being set up to preserve the rest of Erdenheim Farm as a region has always known it.

Eight years later, and almost three years after Dixon's death, that has happened. Yesterday, that foundation spent $12.5 million - from county and local government grants and tax revenue - to buy 91 acres of Erdenheim Farm, adding to its $13.5 million purchase of 98 acres in 2008.

That land will be leased and farmed by Erdenheim Farm's new tenants and majority owners: Radnor executive Peter McCausland and his wife, Bonnie. They bought 259 acres of Erdenheim Farm yesterday to fulfill a long-held dream of owning a farm near Philadelphia and plan to move into its house, after some renovations, within a year.

"We're glad everything worked out and that the farm will be preserved," said Peter McCausland, 59, chief executive officer of Airgas Inc.

Inking the deal required all day yesterday at the eponymous law firm that McCausland helped found in Radnor before he started his industrial gas supply business.

Aside from the publicly funded purchase by the Whitemarsh Foundation, the amount paid for Erdenheim Farm yesterday was not disclosed, though it will become public record when the property deeds are filed.

The Dixon family could not be reached for comment.

In the transaction, the Natural Lands Trust - a nonprofit group to which Widener had willed 117 acres of Erdenheim Farm - and other parties obtained conservation easements on all but 23 acres of the farm.

The agreements bar new construction, save for a handful of houses, on the farm, but Montgomery County and Whitemarsh Township are carving public trails through the farm that will complete a trail connection from Fort Washington State Park to Fairmount Park that authorities have envisioned since 1899.

From the trails, travelers will be able to see how the McCauslands operate what has been a regional treasure for centuries.