Shortly after 8 p.m., the Marin County Fire Department received a report of a fire in a mobile home in the 22000 block of Sir Frances Drake Blvd.
Upon arrival, firefighters found two mobile homes and four cars fully engulfed in flames.
All the residents were evacuated but the two homes and four cars were destroyed, fire officials said.
Six adults and six children were displaced by the fire, according to fire officials.
The Red Cross is providing emergency shelter and supplies for the two displaced families.
The Marin County Fire Marshal, Ross Valley Fire Department, Novato Fire District, Inverness Fire District and the National Park Service assisted with the incident, according to fire officials.
No injuries to fire personnel were reported.
The cause of the fire remains under investigation, fire officials said.