Film Permit requirements vary for cities, state parks, and highways. A county film permit is required for the unincorporated areas, you can get more information on permit requirements for specific locations by contacting the Film Commission.
County Film Permit - https://www.mendocinocounty.gov/government/economic-development/film-permits
Filming on State Parks - http://www.parks.ca.gov/?page_id=24777
California Film Commission - https://film.ca.gov/
Film Liaisons In California Statewide - http://www.filmcalifornia.com/
Filming on California Roadways - https://film.ca.gov/state-permits/caltrans-highways-freeways/
Most filming in Mendocino County does require a permit, check here for more information >>
Mendocino County is a directors dream. Click here to see images >>
Since 1904 some of the most famous movies and commercials have been shot here >>