 Between 1948 and 1956, the Folsom Dam was constructed by the U.S. Army Corps of Engineers below the confluence of the north and middle forks of the American River. Its primary purpose was to provide flood control as the river flowed toward Sacramento. It was built in tandem with the Bureau of Reclamation’s construction of Nimbus Dam downriver.
While building Folsom Dam, a diversion tunnel was constructed that allowed the American River waters to continue flowing toward the Sacramento Valley.
Pictured here Feb. 25, 1955, the 52-ton gate at the intake portal of the diversion tunnel is being shut for the last time. With its closure, water began to fill behind the dam and create Folsom Lake. While carefully controlled during the final phases of construction, the lake now covers between 10,000 and 11,000 surface acres of water, and extends over 10 miles up the south fork and 15 miles up the north fork of the American River.
Photo: Closing the diversion tunnel gate to create Folsom Lake. Feb. 25, 1955. Placer County Museums, Auburn State Recreation Area/California State Parks collection.
 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
Current recruitments include:
 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
Lincoln: Farmers’ Market at Fowler Ranch, Kaiser Lincoln Farmers' Market
Auburn: Auburn Old Town Farmer’s Market – Placer Farmers Market, Sacred Arts Of Tibet Tour In Auburn-Sand Mandala, North Auburn Artists Reception, Farmers Market at Sutter Auburn Faith Hospital, For The Love Of Birds Presented by the Sierra Foothills Audubon Society
Colfax: Community Craft Club, Coffee & Conversation
North Lake Tahoe: Smore’s O’clock, The Village at Northstar Après Music Series, KT Bass Bar Music Series, Throwback Thursdays, Snowfest 2026, Ididarun Sled Dog Race
...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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