The Mountain Fire started Wednesday morning and had grown to 32 square miles (about 83 square kilometers). It was 7% contained Friday morning.
"The fire is burning in steep, rugged terrain, with dry and receptive fuels, which have challenged containment efforts," Cal Fire reported in a statement Friday morning.
Here's a look at where the flames have spread.
If viewing on the mobile app, click here to see the map.
The Mountain Fire prompted evacuation orders for more than 10,000 people. The blaze is threatening more than 11,700 structures in suburban neighborhoods, ranches and agricultural areas around Camarillo in Ventura County, Cal Fire reported Friday.
The Associated Press contributed to this report.