Mile Rocks Lighthouse - San Francisco, CA
Posted by: 
DougK
N 37° 47.559 W 122° 30.614
10S E 543121 N 4182922
Mile Rock Lighthouse in San Francisco, California, consists of the base of the original lighthouse tower. The tower was removed when the lighthouse was deemed to difficult to access and automated signals were put in place.
Waymark Code: WMAEWE
Location: California, United States
Date Posted: 01/06/2011
Views: 6
When I first saw this structure off shore, I did not know what it was. Over time, I discovered that it was the remains of the Mile Rocks Lighthouse.
Excerpted from Lighthouses around San Francisco Bay:
Mile Rocks—Two large rocks named Mile Rock and Little Mile Rock are located just off San Francisco’s Point Lobos. The rocks were first marked with a bell buoy in 1889. After a shipwreck off Fort Point in 1901 in which many people died, it was decided to build a lighthouse here.
The lighthouse was essentially a cylinder on top of a rock. Families could not live on the station because it was so small, the noise from the fog signal was deafening, and it was often difficult to get on and off the rocks because of powerful waves. Mile Rocks lighthouse was automated and then closed in the 1960s. The tower was removed, and the base is used as a helicopter landing.
Excerpted from the Mile Rocks Light webpage:
The orange and white caisson beyond Land's End in San Francisco is Mile Rocks Lighthouse. A victim of modernization, this seemingly humble structure was one of the great lighthouse engineering feats of all time.
Mile Rocks is a a pair of stones about half a mile north of Point Lobos in San Francisco. The larger of the two rocks is 40 feet by 30 feet, and rises about 20 feet above sea level. Mariners considered these to be a serious hazard due to fog and strong currents in the area. In November 1889, the Lighthouse Board marked the rocks with a bell buoy. The buoy proved inadequate, as strong currents would sometimes submerge the buoy. There was a fog bell at Fort Point, but this was often inaudible at Mile Rocks. The buoy was removed in 1890.
In 1901, the Rio De Janeiro was wrecked near Fort Point. 146 lives were lost in the disaster. Outrage over the tragedy led to the establishment of a more powerful fog signal at Fort Point, as well as approval for a new lighthouse at Mile Rocks.
In the 1960's, despite protests from the general public, the tower of Mile Rocks was dismantled in the name of progress. The Coast Guard had deemed the station difficult to access and best suited to automation. The tower was removed and a helicopter pad built atop the caisson. Conversion was completed in August 1966. Airhorns served as the fog signal, and an aerobeacon replaced the Fresnel lens. Solar panels were installed to power the station.
Note: This light is only accessible by helicopter. The posted (actual) coordinates were taken from Wikipedia. The lighthouse can be seen at many places at Land's End along the Coastal Trail. The closest you can get to to it on land is at Mile Rock Beach.