The pilot, the lone occupant of the plane, crashed just after 11 a.m. after taking off from the airport located at 400 Smith Ranch Road, San Rafael Fire Chief Chris Gray said.
The pilot walked away from the crash with only minor injuries and the plane sustained minor damage, Gray said.
Federal Aviation Administration spokesman Ian Gregor said he did not immediately have information this afternoon on the identity of the pilot or the type of aircraft that crashed.
Authorities do not yet know what caused the plane to crash.
San Rafael fire Battalion Chief Jeff Buscher said the pilot maneuvered a controlled crash that landed the plane belly down into a marsh. The aircraft then hit a ditch and spun around.
The damaged plane was resting under power lines near the airport this afternoon and fire crews were monitoring it for possible fuel spills, Buscher said.