The temblor struck about 50 miles west of Eureka in Humboldt County at 10:18 p.m. It had a depth of 4.3 miles.
No tsunami warnings were expected. It was followed by about a half-dozen aftershocks, including one of magnitude 4.6.
There were no immediate reports of damage or injuries, according to the Humboldt County Sheriff's Department.
People reported feeling the temblor in Crescent City, Redding and the Bay Area.
The Associated Press contributed to this report.
