The 11,405-acre Crown Fire had destroyed two homes and a historic wood bridge north of Los Angeles before the wind changed direction and blew the blaze back on itself and toward open desert.
The fire, which began Tuesday on the edge of the Mojave Desert, was 50 percent contained Thursday and no longer a threat to homes, fire officials said.
``It's in the sand, the rock, the dirt, that type of terrain, which makes it easier for us to get a line around it,'' said Los Angeles County fire Capt. Dennis Cross.
Meanwhile, cooler overnight temperatures aided firefighters battling a 135-acre brush fire that broke out late Wednesday near Temecula, 85 miles south of Los Angeles.
That blaze, named the Martin Fire, was 50 percent contained Thursday with full containment expected by Friday, said Patrick Chandler, a spokesman for the Riverside County Fire Department.
Two other large fires that raged earlier in the week were fully contained. The Foothill Fire blackened 6,060 acres near the Los Angeles suburb of Santa Clarita, and the Pine Fire scorched 17,418 acres and destroyed three homes near Lake Hughes.
There was no estimated time of containment for the Acton fire, which was being fought by 2,582 firefighters. Seven suffered minor injuries.
Angeles National Forest spokesman Stanton Florea said investigators determined the blaze was human-caused.
``Whether or not it was intentional or accidental is still under investigation,'' he said.