The original Point Bonita Lighthouse, a brick tower, was located too high. Unlike the East Coast of the United States, the West Coast has dense high fog, which leaves lower elevations clear. The original light was above sea level so the second order Fresnel lens was often cloaked in fog and could not be seen from the sea. In 1877, the lighthouse was moved to its current location at above sea level. The United States Coast Guard currently maintains the light and fog signal.
Historical Information from USCG web site:
- Point Bonita Light Station had the first fog signal on the West Coast. It was an Army surplus 24-pounder siege gun.
- This light is the only one in America that can be reached only by crossing a suspension bridge which is a replica of the Golden Gate Bridge.
- In 1877 the lighthouse was moved to its current location because the original location was often too obscured by fog for the light to be visible from the bay. This location required the builders to overcome many challenges, including the need for a hand carved, long hard rock tunnel.