© NASA/EPASatellite imagery shows the vast Thomas Fire, north of Los Angeles, which has spread as far as the Pacific coast
The Thomas fire has burned more than 1000sq km - an area greater than New York City, Brussels and Paris combined.
The blaze broke out in Santa Paula in early December and has moved west towards the coast, one of several major fires in California in recent months.
Thousands of firefighters have been deployed to bring it under control.
Most of California's largest wildfires have been recorded this century. Scientists say the warming climate and spread of buildings into wilderness areas have contributed.
The Thomas fire slowly eclipsed previous record-setting blazes, finally overtaking the 2003 Cedar fire in San Diego County, which burned 273,246 acres.
It follows a series of deadly fires in the state's wine country in October that burned more than 10,000 homes and killed more than 40 people.
The Thomas fire has destroyed more than 1,000 buildings and claimed the life of one firefighter - Cory Iverson, a father of one from San Diego whose wife was expecting another child.
State fire agency Cal Fire says the Thomas blaze is now 65% contained and expected to continue to slow. Controlled burns by firefighters may cause some temporary expansion, it said.
Seven of California's 10 largest fires on record have occurred since 2000. Two were in the 1970s and the earliest was in 1932 - the Matilija fire which, like the Thomas fire, burned through Ventura County.
Comment: Thomas Fire Becomes Third-Largest Ever as California Experiences Another Record-Breaking Wildfire Season