The Charlie Fire burning near Castaic and Santa Clarita grew only slightly overnight, reaching just under 3,400 acres in size on Sunday morning, officials said.
The wildfire broke out about 2:30 p.m. Saturday in Charlie Canyon near Castaic, in the area of Charlie Canyon Road and Tapia Canyon Road, Los Angeles County Fire Department Inspector Joey Marron said.
Residents of about 20 homes in San Francisquito Canyon that had been under evacuation orders were given the all-clear to return, Santa Clarita city officials said.
Lake Hughes Road are closed in the area, north of Castaic Lake's main boat launch, whle Lake Hughes Road was reopened to residents only on Sunday afternoon, L.A. County fire officials said.
More than 300 firefighters, aided by water-dropping helicopters and the two leased Canadian Super Scooper jumbo jets, have built containment lines around 20 percent of the fire, according to Los Angeles County Fire and Forest Service officials.
Sunday's plan primarily involved constructing and reinforcing containment lines, officials said.
"Aircraft are being used to support ground crews with water and retardant drops," the statement said.
No injuries or property damage have been reported.
The cause of the fire remains under investigation.
Temperatures were predicted to climb above 90 degrees Sunday, but relative humidity levels were expected to stay above 15 percent, Forest Service officials said. Winds of 8 to 15 mph were in the forecast.
Authorities moved the Lake Hughes Road closure up beyond Castaic Lake's Upper Lake main boat launch to allow boaters and campers access to the lake's eastern side, Los Angeles County fire officials said. The west side of the lake is expected to remain closed to the public for a longer duration.