The blaze, called the Muir Fire, was reported around 10:45 a.m. and burned a total of 50 acres combined so far on both sides of Highway 1, according to the Marin County Fire Department.
Highway 1 is temporarily closed between Panoramic Highway and Muir Woods.
Just before 3 p.m., fire officials said forward progress of the wildfire stopped and was 10 percent contained.
No structures are threatened and no evacuations have been ordered.
Ten fire engines are either already there or en route and there are two fire crews, officials said.
Motorists were advised to avoid the area.
Stay with ABC7 News for the latest details on this developing story.