A $70 Million Record in Hillsborough, and What Marin Should Read Into It

Key Takeaways

• A 12.33-acre Hillsborough estate closed at $70 million on August 6, the highest residential sale reported in Northern California this year and double the previous Hillsborough record of $35 million.
• It was listed at $88 million. The final price is roughly 20.5% below the original asking price, after a reduction to $78.8 million in May and about 141 days on the market.
• It is not a regional record. The Bay Area’s all-time high remains $117.5 million in Woodside from 2012, and an $85 million Woodside sale closed less than a year ago.
• Marin’s ceiling has not been tested since 2015, when Locksley Hall in Belvedere sold for $47.5 million. That figure still stands.
• The lesson travels down-market. If the year’s largest sale still closed 20% under ask, ambition in pricing is not a strategy at any price point.

What sold, and for how much

On August 6, a 12.33-acre estate on Ralston Avenue in Hillsborough closed for $70 million. It is being reported as the highest residential transaction in Northern California so far this year, and it is unambiguously the highest sale ever recorded in Hillsborough, doubling the town’s previous record of $35 million set in 2022.

The property is extraordinary by any measure. A 12,404-square-foot main residence with a 4,612-square-foot guest house, built over six years on three assembled parcels. Italianate architecture by Andrew Skurman, interiors by Suzanne Tucker, and grounds that include a 150-seat amphitheater, an Olympic-size sunken tennis court, an eighteen-hole putting green, and fountains modeled on the Bellagio. It was listed by Jennifer Gilson of Golden Gate Sotheby’s International Realty, who has said the buyer works in artificial intelligence.

That is the version of the story that circulated when the sale closed. Here is the part that did not make the captions.

The number the headlines skipped

The estate came to market at $88 million. It was reduced to $78.8 million in May. It closed at $70 million.

That is roughly 20.5% below the original asking price, after about 141 days on the market and a marketing period that began the previous autumn.

I want to be careful here, because this is not a criticism of anyone. A $70 million sale is a remarkable achievement, the property is genuinely singular, and pricing a home with no true comparable is closer to art than arithmetic. When you have built something no one has built before, there is no data to price against.

But the fact remains, and it is the most useful thing in the entire story: the largest residential transaction in Northern California this year still closed 20% under its original ask.

What this sale is, and what it is not

Records get reported loosely, so it is worth being precise about which one this is.

It is the highest sale ever in Hillsborough, by a wide margin. Two independent outlets confirm the prior record was $35 million.

It is the highest residential sale reported in Northern California in 2026 to date. That framing originates with the listing agent rather than an independent survey, and I could not find anything larger, so I would treat it as accurate but agent-sourced. The nearest 2026 figure I can verify is a $56 million off-market sale in Pacific Heights in April.

It is not a Bay Area record. That remains the $117.5 million Woodside estate purchased in 2012, which was briefly the most expensive home sale in the United States.

It is not even the largest Bay Area sale of the past twelve months. Green Gables in Woodside closed at $85 million in September 2025.

None of that diminishes the transaction. It does mean the number should be read as a strong year, not a broken ceiling.

Where this leaves Marin

Here is what I keep returning to.

Marin County’s record residential sale is still $47.5 million, set in August 2015 when Locksley Hall in Belvedere traded. Eleven years later, it stands.

More telling: that same house sold again in August 2025, for $43.5 million. Below its 2015 price. The buyer went on to assemble roughly $73 million of Belvedere property across four homes, so this was not a case of weak demand. It is a case of a ceiling that has simply not been pushed.

Marin’s highest active listing today is a Belvedere Island compound asking $50 million, a 1967 William Wurster house with landscape architecture by Thomas Church. I wrote about it when it came to market this spring. A sale at ask would finally reset the county record. It has not yet traded.

So the picture across the bay is this. The Peninsula printed a $70 million number this August. Marin’s top of market has been quietly compounding, with Ross average prices up 65% and Kentfield up 45% last quarter, but the very top has not been tested in over a decade.

I do not read that as a weakness. Marin has never been Atherton or Woodside, and it has never wanted to be. Our top tier is smaller, more architecturally idiosyncratic, and far more privately traded. What it does mean is that if a Marin property is going to reset the record, the buyer almost certainly will not come from a bidding war. It will come from a relationship.

The buyer detail worth noticing

The Hillsborough buyer works in artificial intelligence.

That is not incidental, and it is the same current I wrote about in the piece on San Francisco buyers moving north. This cycle’s wealth is concentrated in the Bay Area, it is arriving liquid, and it is buying at both ends of the map. Off-market luxury volume in San Francisco has grown roughly 71% year over year, with private deal counts rising from 98 to 158.

A buyer of this profile is not comparing Hillsborough to Belvedere in any literal sense. But they are the same buyer pool, and they are increasingly comfortable transacting privately at the very top. That has a direct consequence for Marin owners: a meaningful share of the county’s highest-value trades never appear on the MLS at all, which means the public record understates both supply and demand at the top.

What I would tell a Marin seller right now

Three things.

Ambition is not a pricing strategy, at any number. If an $88 million ask on a genuinely one-of-one property required two reductions and five months to find its buyer, the same physics apply to a $4 million home in Kentfield. In Marin this quarter, homes going under contract within thirty days achieved close to 105% of their original asking price. Homes sitting past 120 days achieved roughly 84%.

A price reduction is not a failure. This seller reduced twice and still set a town record by a factor of two. The reduction was part of the path to the record, not a departure from it. I have watched too many sellers treat the first adjustment as a defeat and lose a season to it.

Scarcity and preparation still decide the outcome. The Hillsborough estate had no comparable and still needed the right buyer to appear. Nothing about a strong market removes that requirement. It only shortens the wait.

If you are weighing a move in Marin this year and want a candid read on where your home actually sits, I am glad to have that conversation.

Frequently Asked Questions

What was the highest home sale in Northern California in 2026?

A 12.33-acre estate on Ralston Avenue in Hillsborough closed for $70 million on August 6, 2026. It is reported as the highest residential transaction in Northern California so far this year, though that characterization originates with the listing brokerage rather than an independent survey.

Did the $70 million Hillsborough sale set a record?

It set the record for Hillsborough, doubling the town’s previous high of $35 million from 2022. It did not set a Bay Area record. That remains a $117.5 million Woodside sale from 2012, and an $85 million Woodside sale closed in September 2025.

What did the Hillsborough estate originally list for?

It came to market at $88 million, was reduced to $78.8 million in May 2026, and closed at $70 million. The final price is approximately 20.5% below the original asking price after roughly 141 days on the market.

What is the most expensive home ever sold in Marin County?

Locksley Hall in Belvedere, at $47.5 million in August 2015. That record still stands. The same property resold in August 2025 for $43.5 million, below its 2015 price.

What is the most expensive home for sale in Marin County right now?

A Belvedere Island compound asking $50 million, designed by William Wurster in 1967 with landscape architecture by Thomas Church. A sale at the asking price would set a new Marin County record.

What does a record Peninsula sale mean for Marin homeowners?

Directly, very little, since the two markets serve different buyers. Indirectly, it confirms that Bay Area ultra-luxury demand is strong and increasingly driven by technology wealth transacting privately. The more portable lesson is about pricing: even the year’s largest sale closed well under its original ask.

About Lauren Hamblet

Lauren Hamblet is a luxury real estate advisor with Coldwell Banker Global Luxury, serving Marin County, San Francisco, and the broader Bay Area. Twenty-five years across the Ross Valley and southern Marin, alongside four generations of San Francisco family history, have shaped her quietly sophisticated, globally informed approach. Learn more about Lauren or contact her.