Firefighters in Southern California made significant progress on Friday toward containing a wildfire that began in Ventura County and had spread into Los Angeles County, leaving thousands of residents under orders to leave the area.

The blaze, called the Canyon fire, began early Thursday afternoon near Lake Piru, a reservoir about 60 miles northwest of downtown Los Angeles. The fire was initially reported to have burned 30 acres, but it expanded quickly and had burned about 5,300 acres as of Friday morning, according to the California Department of Forestry and Fire Protection, the state’s main firefighting agency.

By the morning, firefighters had been able to contain at least 25 percent of the fire as it continued to spread east in Los Angeles County, officials said. The Ventura and Los Angeles County Fire Departments were leading the effort to contain the fire as it burned into the night, with 400 personnel deployed.

In Hasley Canyon, an unincorporated area near Santa Clarita, Calif., the fire had destroyed at least two structures, a shed and a home, and left acres of hillside scorched and covered in ash. Firefighters were patrolling neighborhoods in trucks and golf carts, looking for potential hot spots as temperatures began to rise in the afternoon.

Parts of the hillsides in Hasley Canyon continued to burn on Friday afternoon. Most of those smoldering pockets were in areas that had already burned, leaving less of a chance for them to spread.