Bill Foley is adding another prominent Sonoma County property to his growing empire.

The emerging wine mogul has agreed to purchase the 16-room Les Mars Hotel, which is a sanctuary for the rich and famous. Room prices range from $575 to $725 a night.

Foley, who is a self-made billionaire, purchased Chalk Hill Winery in August and bought Sebastiani Vineyards and Winery in 2008.

Les Mars also is home to the high-end Cyrus Restaurant, which has a long-term lease agreement to stay in the building.

Foley continues to shop for other Sonoma County properties and is still looking to purchase another flagship winery along Highway 29 in Napa County, said Andrea Smalling, vice president of marketing for Foley Family Wines.

"He is generally looking for vineyards and wineries. And we are still looking for that good Napa property," Smalling said. "A lot of people are bringing him deals, and he usually takes a look at anything. He is always interested in new opportunities."

Foley has no plans to drastically alter the hotel's business model, Smalling said. It will likely serve as the temporary home of his visiting guests and other VIPs who visit Chalk Hill Winery.

Les Mars Hotel was built at a cost of $3.5 million but had a list price "well below development cost," according to the listing agent's website. The tentative purchase price was not disclosed.

The deal is on track to close in November, Smalling said.

David and Sarah Mars spent four years developing and designing the hotel before they opened it in 2005. The husband and wife laboriously planned all the intricate details of the luxury hotel, from Travertine marble imported from Italy to thick limestone hauled from Texas and Utah for the pool area.

Foley purchased his first winery less than 15 years ago and is now among the top 30 U.S. wine producers. His company, Foley Family Wines, owns more than 11 wineries.

In all, Foley Family Wines produces about 850,000 cases of wine annually.

Foley declined to say how much he agreed to pay for the 1,270-acre Chalk Hill estate, which included the buildings, 278 acres of vineyards, a winery, a pavilion, an equestrian center and the palatial main residence. Sources close to the deal said the price was in the range of $70 million.

Foley made his fortune building the nation's largest title insurance company, Fidelity National Title. He purchased his first title company in 1984 and quickly began adding other title companies. By 2003, his company was number 262 on the Fortune 500 list and generated more than $10 billion in annual revenue.

By 2007, as chairman of the company, he was no longer involved in daily management. That's when he began investing heavily in wineries.

Now he plans to split his time between Sonoma County and Montana, where he also has invested heavily in recent years. He plans to move into the mansion at Chalk Hill Winery, which is about a 15-minute drive from Les Mars Hotel.