The most expensive sale of residential Vineyard real estate was completed on Tuesday in a law office in Boston. An old summer family sold 80 acres of north shore property that fronts Vineyard Sound in West Tisbury for $12 million.

The property, in proximity to Paul's Point, had been in the Albridge C. Smith family since 1943. The sellers were his two daughters: Margaret (Trika) Smith-Burke of Connecticut and Cary Hart of California. The property was put on the market early last winter.

The purchaser was Shore Realty Trust, on behalf of an unnamed buyer. The real estate transaction was handled by David C. Thompson of Land Vest Inc. in Edgartown.

The 80-acre parcel is pristine, undeveloped land that overlooks the Sound and offers views of the Elizabeth Islands. The landscape is as varied as the north shore gets and in many respects resembles Cedar Tree Neck, not far away. There are rolling hills with rich, thick woodlands. A stream runs through the property and there is a swamp that becomes a pond during wet periods of the year. Nearer the shore there is typical coastal habitat that include beach trees and short oaks. There is a wide variety of plant life. Beach frontage runs 1,060 feet, most of it sand.

The land once belonged to the late Sen. William Morgan Butler of Massachusetts, who owned Mohu and a good portion of Paul's Point. Except for a dirt road and an old homestead, the land is undeveloped.

Eric Peters, an Island attorney representing the sellers, said the family had a long history with the property. The property was purchased from Mary W. Butler, the senator's widow, by Albridge Clinton Smith 3rd and his wife, Margaret Mitchell Richter, and mostly left unaltered. A small house was built on the property, fashioned from two Quonset huts that were trucked to the property during the war years. For years the property lacked such amenities as electricity and a telephone.

Mr. Smith was an attorney. He and his family spent a lot of time fishing and in traditional Island summer recreation. He was known for his neighborhood clambakes held on the beach.

"They had no electricity for many years," said Mr. Peters. They kept in touch with the rest of the world by using a field telephone that connected them to a neighbor; otherwise the family was very much apart from the rest of the world.

Mr. Peters said of the sellers: "They continued the traditions of their parents, caring for the property and maintaining a love for the Vineyard for over 50 years. They hope the new owners and their children will establish a similar long-lasting tradition."

The buyers have asked that they remain anonymous.

The property will remain mostly undisturbed. Mr. Thompson said: "It is certainly going to remain in their family entirely and likely never be subdivided. If it were subdivided, it would be to create a conservation piece."