 The Hidden Treasure Mine located on the Foresthill Divide was the most productive drift mine in California. Drift mines tunnel horizontally into the buried gold-bearing gravel of ancient river channels that have been encased underground. It is estimated that between $4 million and $5 million in gold was extracted by this operation from 1875 to 1910, which would be between $870 million and $1.1 billion in 2026.
The town of Sunny South was a company town, founded at the entrance of the mine on the south-facing hillside above El Dorado Canyon. Miners working for wages brought their families to this rugged location, and the town’s population grew to a peak of about 350 people, with nearly 50 families.
In 1896, when the Hidden Treasure tunnel was nearly 2 miles deep, a new tunnel was dug 2 miles above Sunny South. At the new entrance, the town of Bullion was built, and the residents of Sunny South abandoned the old townsite. A hydroelectric power station was installed to provide electricity to the mine at Bullion, which now included an electric locomotive that ran on rails through the main working tunnel.
In June 1910, a cave-in forced the mine to close, and operations never reopened. The town of Bullion was abandoned. A major fire in 1924 destroyed what was left of Sunny South, and very little remains to mark the site of the famous Hidden Treasure Mine.
Photo: Hidden Treasure Mine at Sunny South. Circa 1880. Placer County Museums, Placer County Historical Society collection.
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 Whether it’s representing your community or sharing your expertise on topics like agriculture or parks, there are always opportunities for you to help advise county leaders on the issues that matter to you most. Recruitment is open now to fill seats on the following committees or commissions, among others. Learn more and apply
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 Don’t miss the fun coming this next week in...
Roseville: Mahany Park Certified Farmers' Market, Maidu Park Farmers' Market, Roseville Fountains Farmers' Market, Kaiser Riverside Farmers' Market, Kaiser Eureka Farmers' Market, Sutter Roseville Farmers Market, Dry Creek Greenway East Grand Opening
Rocklin: 26 Parks in 2026, Firefighter storytimes, Rocklin Community Festival
Lincoln: Farmers’ Market at Fowler Ranch, Kaiser Lincoln Farmers' Market, 2026 National Competition “Feats Of Clay”
Loomis: Loomis Beer Fest
Auburn: Auburn Old Town Farmer’s Market – Placer Farmers Market, Farmers Market at Sutter Auburn Faith Hospital, Auburn Music On The Square, Auburn Cruise Night, State Theater Presents: The Golden Age Of Radio, Auburn Bike Month Speaker Series, Stories Underfoot - Central Square Tiles
Colfax: Colfax Farmers’ Market
North Lake Tahoe: Throwback Thursdays, Line Dancing Fridays
...and many Placer County Library and Placer County Museum events.
Visit our regional partners to discover more of the fun happening right here in Placer County!
Placer County Visitors' Bureau
North Tahoe Community Alliance
Tahoe City Downtown Association
The Arts Council of Placer County
Placer Valley Tourism
PlacerGROWN
Placer Wine Trail
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