Full containment of the fire is expected by Tuesday, officials said.
The fire began Saturday near Lake O'Neill at the sprawling base, and is being fought by 339 firefighters from the Camp Pendleton Fire Department, the U.S. Forest Service and other agencies, the Los Angeles Times reported.
Minor damage was reported to four buildings on the base, and no injuries were reported. Patients at an on-base hospital were transferred to local civilian hospitals after a power outage at the hospital, the newspaper said.
About 330 people who left their homes returned home Sunday, authorities said. The residents of the base had been evacuated Saturday afternoon when the brush fire threatened their homes, U-T San Diego reported.