The sheriff has asked relatives of the missing to submit DNA samples to hasten identification of the dead. But he said some of those unaccounted for may never be identified.
The were other smaller blazes in southern California including the Woolsey Fire that is linked to three fatalities and destroyed at least 500 structures near the Malibu coast west of Los Angeles.
Scientists say two seasons of devastating wildfires in California are linked to drought they say is symptomatic of climate change.
Two electric utilities say they sustained equipment problems close to the origins of the blazes around the time they were reported.
The White House said on Thursday that President Donald Trump plans to visit the fire zones on Saturday to meet displaced residents. Critics say Trump politicized the fires by casting blame on forest mismanagement.
Cal Fire said 40 percent of the Camp Fire's perimeter is contained, up from 35 percent, even as the blaze footprint grew 2,000 acres to 141,000 acres (57,000 hectares). The Woolsey fire is 57 percent contained.
Public schools in Sacramento and districts 90 miles (145 km) to the south, and as far away as San Francisco and Oakland, said Friday's classes would be canceled as the fire worsened air quality.
Many of those who survived the flames but lost homes stayed with friends or relatives or at American Red Cross shelters.
