Officials fear that at least 150 people are still unaccounted for.
The blaze has also destroyed a part of the state's wine region, forcing the evacuation of thousands.
Sonoma County alone counted for nine deaths.
More that 1500 homes have been completely destroyed by the flames, according to local authorities, who added that north San Francisco's Santa Rosa was the worst affected town.
The BBC quoted state fire chief Ken Pimlott as saying that "17 fires had burned about 115,000 acres (26,000ha) in the past 24 hours."
An emergency has been declared in seven counties, including Napa and Sonoma, by California Governor Jerry Brown.
Following the carnage, a disaster declaration has been approved by US President Donald Trump.
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