The Trailhead Fire along the middle fork of the American River burned has more than 2,000 additional acres since Saturday but still had not destroyed any structures as of Monday morning.
The fire has consumed 5,444 acres and is 25 percent contained.
The Appaloosa Fire in Calaveras County has spread to 425 acres and is 25 percent contained.
Ten other fires are active across the state from San Diego to near the Oregon border, according to Cal Fire. There are 4,800 firefighters battling the blazes.
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Cal Fire reported that containment lines for the Trailhead Fire in Placer County held overnight and that firefighters in El Dorado County put a fire line in place from the hills west of Volcanoville to the middle fork of the American River.
Other crews strengthened lines protecting Volcanoville, a rural community where a mandatory evacuation order is in effect. The nearby community of Todd Valley is under a voluntary evacuation order.
Three injuries have been reported as 2,123 personnel work to subdue the Trailhead Fire. Cal Fire expects to contain the fire by Wednesday.
The fire started Tuesday afternoon; the cause remains under investigation.
The Appaloosa Fire, which began on Saturday, is on Appaloosa Road at Pinto Drive, two miles south of Highway 4. One firefighter has been injured and no one has been evacuated.
Other fires in Fresno, Santa Barbara, Siskiyou and Los Angeles Counties now range across tens of thousands of acres.
Of the fires reported by Cal Fire, the Erskine Fire in Kern County is the largest at 48,019 acres. The fire is now 95 percent contained.
Another fire in Kern County, the Deer Fire, burned 1,785 acres and is 60 percent contained.