The Colorado Fire, which has been active since Friday, was 5 percent contained, the California Department of Forestry and Fire Protection (Cal Fire) said.
A 20-mile stretch of State Highway 1, a scenic north-south route on the Pacific Coast, was closed from near the beach town of Carmel-by-the-Sea to Andrew Molera State Park.
About 400 people in Monterey County were evacuated from 1,100 structures, a spokeswoman for the American Red Cross said, citing county reports.
California has long had an active wildfire season, but in recent years, fueled at least in part by climate change, it has grown longer and more punishing.
Last year, the wildfire season started unusually early amid an ongoing drought and low reservoir levels, Cal Fire said.
In January 2021 alone, the state battled 297 fires on 1,171 acres, the office said.
The Colorado Fire is the only fire listed on Cal Fire's incident list so far in 2022.