More than 5,000 firefighters have now got the 16-day-old blaze 45 percent contained, the California Department of Forestry and Fire Protection said.
Officials expect the fire will be fully contained by Sept. 20.
Crews are making good progress, particularly on its northwest side, U.S. Forest Service spokesman Trevor Augustino told the Los Angeles Times.
But the central Sierra Nevada blaze is continuing to expand to the northeast, he said.
No structures have burned since last week, when officials reported 111 were destroyed -- mostly small cabins and outbuildings, but 11 homes were among those destroyed.
Fighting the blaze, the nation's largest active forest fire, has cost more than $60 million in state and federal funds, Augustino said.
The cause of the fire, which started deep in the Stanislaus National Forest Aug. 17, is under investigation.
The fire got its name because it started near a Stanislaus forest lookout point nicknamed the "Rim of the World."
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