According to the Wall Street Journal newspaper, the site in St Helena will comprise a four-bedroom home measuring around 6,500 square feet plus a furnished three-bedroom guesthouse.
The estate will also include a 776-square foot spa house, a tennis court, an infinity pool at the main house and a lap pool at the guesthouse.
According to developer Patrick Cahill, who bought the site for about $2.75 million in 2011, some 14 acres of Cabernet Sauvignon grapes have also been planted on the estate, should the buyer choose to build winemaking facilities.
The estate is listed with luxury real estate company Sotheby’s International Realty.
Napa Valley is a renowned wine-producing region north of San Francisco, with hundreds of vineyards set amid rolling hills.