By Betty Yu

HEALDSBURG (CBS SF) — Sales of homes priced at more than a million dollars across Sonoma County are on the rise – in large part because of a boom in Silicon Valley buyers.

“Traditionally Napa is where you’re going to see the $10-plus million price tag, but in the last 5 years, we’ve really seen an uptick in the amount of homes priced at $10-plus million in Healdsburg for example,” said luxury real estate broker Justin Fichelson.

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On Dry Creek Road, there is a $15.9 million estate now on the market. It sits on 50-acres surrounded by rolling vineyards, oak trees and views of Dry Creek Valley. The grounds feature an entertainment barn with a gym, a pro-style putting green, a tree house and a 6,000-square-foot home.

It comes with a spacious kitchen, wine grotto, 3 bedrooms, and 4-and-a-half baths.

Agents say clients are also noticeably younger.

“Sonoma’s more private, they like kind of being avant-garde doing the different thing. So while everyone is traditionally going to Napa to buy their vacation home, they want to go where it’s more private,” said Fichelson.

In 2012 – the median house price in the county was $316,500. Today – it’s nearly double that at $625,000, according to Paragon Real Estate Group.

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Within the county – the city of Sonoma and Santa Rosa had the largest number of pricey sales in the last year.

A 44-acre estate on Guenza Road in Santa Rosa – complete with a pool, vineyards, 7 bedrooms, 6 bathrooms, a 30-stall horse facility and pastures and a private lake is listed at $3.5 million.

“There haven’t been a lot of homes built in the last 10 plus years so inventory levels are very low, and a million dollars doesn’t buy you much up here,” said Artisan Sotheby’s International Realty broker Doug Swanson.

Swanson specializes in wine country property. He says 80 percent of his buyers come from outside the county – and of those – half are from the Bay Area.

Some are buying because it’s still cheaper than living in San Francisco. Others are investing in a second home in a city that gives them that small town feel.

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“I thought that we were going to reach another plateau but in the last 6 months it’s just kind of broken through that and it’s still going, I don’t see an end to that right now,” he said.