The historic Seaweed estate on Bellevue Avenue had been owned by the family of the late Rita Dolan Sellar — the grandmother of Sandra Whitehouse, wife of U.S. Sen. Sheldon Whitehouse.

Gustave White photo

It was on the market for more than a year, but Seaweed, a historic estate at 740 Bellevue Ave. in Newport, was sold Tuesday at the highest price recorded for a house in Rhode Island so far this year — $7,750,000.

According to the listing broker, Paul Leys, of Gustave White Sotheby’s International Realty, the waterfront estate on Newport’s Cliff Walk had been owned by the family of the late Rita Dolan Sellar. She was the grandmother of Sandra Whitehouse, wife of U.S. Sen. Sheldon Whitehouse.

The name of the buyer was not disclosed. The house had been listed for sale with an asking price of $10,250,000.

Leys said the asking price had included a separate carriage house property with a Ledge Road address, but the buyer was not interested in it.

Seaweed probably got its unusual name because it overlooks Bailey’s Beach, and a lot of seaweed washes up there, Leys guessed, but he noted that “it’s not the most attractive name” from a marketing standpoint.

Leys said Seaweed was designed by architect Horace Trumbauer, who also designed two other Bellevue Avenue estates: Clarendon Court and Miramar.

Another famous Newport mansion, Rough Point, built for Frederick William Vanderbilt but later owned by the late tobacco heiress, Doris Duke, is nearby, at 680 Bellevue Ave.

The 2006 sale of Miramar, for $17,150,000, was the single highest sales price ever recorded for a Rhode Island house sold through the Multiple Listing Service, according to Donna M. McGinn, administrator of the statewide MLS.

Last year, actor Nicolas Cage bought the sprawling Gray Craig estate in Middletown for $15.7 million.

According to McGinn, there have been seven house sales in Rhode Island with prices over $4 million this year, all located in Charlestown, Jamestown, Westerly or Newport.

The other six high-end sales include: 359 West Beach Rd. in Charlestown (Jan. 15), $4.1 million; 1088 East Shore Rd., Jamestown (March 7), $5,202,000; 11 Spray Rock Rd., Westerly (March 17), $5.8 million; 7 Manatuck Ave., Westerly (April 18), $6 million; 340 East Shore Rd., Jamestown (July 31) $6.9 million; and 275 Beavertail Rd., Jamestown (Sept. 29), $4,250,000.

cdunn@projo.com