POINT BONITA LIGHT
State: CALIFORNIA
Location: POINT BONITA /
SAN FRANCISCO BAY ENTRANCE
Nearest City: SAUSALITO
County: MARIN
Year Station Established: 1855
Year Automated: 1980
Year Existing Historic Tower
Constructed: 1877
Point Bonita Light
Existing Historic Tower:
Is the Light Operational? YES
Date Deactivated: N/A
Foundation Materials: MASONRY
Construction Materials: BRICK/CEMENT
Markings/Patterns: WHITE
Shape: HEXAGONAL ON FOG SIGNAL BUILDING
Relationship to Other Structures:
INTEGRAL
Tower Height: 33/Height of Focal Plane:
140
Original Optic: SECOND ORDER, FRESNEL
(1877)
Present Optic: SECOND ORDER, FRESNEL
(1877)
Lens Disposition: ORIGINAL LENS STILL IN
OPERATION
Previous Tower(s):
Construction Date: 1856
Description: BRICK TOWER ON CAPE COD
DWELLING
Fate/Disposition: BUILT AT TOO HIGH AN
ELEVATION, SO REPLACED
Newer Tower? NO
Existing Fog Signal Building? YES
Year Constructed: 1903
Construction Materials: BRICK
Architectural Style: 1-STORY RECTANGULAR
Fog Signal Type: ELECTRIC
KLAXON/ORIGINAL: CANNON, BELL
Existing Keepers Quarters? NO
(DEMOLISHED)
Other Structures: 3 CISTERNS (1872,
1877, ca. 1890), OIL HOUSE (1877),
GARAGE, STORAGE BUILDING, RADIOBEACON
(ca. 1981), TUNNEL (1876), BRIDGE (1954)
Owner/Manager: U.S. COAST GUARD/NATIONAL
PARK SERVICE
Current Use: ACTIVE AID TO NAVIGATION IN
NATIONAL PARK
Open to the Public? CALL FOR DATES AND
TIMES
Access: GOLDEN GATE NATIONAL RECREATION
AREA / OFF U.S. 101(REQUIRES ONE-MILE
WALK FROM PARKING LOT)
Public Phone: 415-556-0560
National Register Status: LISTED: POINT
BONITA LIGHT STATION (LIGHT STATIONS OF
CALIFORNIA)
Miscellaneous:
SITE OF FIRST WEST COAST FOG SIGNAL, FOG
CANNON (1856-1858), REPLACED BY A BELL;
ORIGINAL TOWER TAKEN DOWN 1907
NOTE: The tunnel to the suspension
bridge/lighthouse is open Saturdays,
Sundays and Mondays from 12:303:30 pm.
However the lighthouse is not accessible
due to the suspension bridge closure.
Currently the bridge is due to be
replaced and open to the public in the
Spring of 2012.
Point Bonita today is part of the
largest urban national park in the
United States, the Golden Gate National
Recreation Area. A secret jewel of the
Bay Area, Point Bonita is still an
active lighthouse. The U.S. Coast Guard
maintains the lighthouse and the
National Park Service provides access to
visitors.
Point Bonita Lighthouse is reached by a
halfmile trail that is steep in parts.
Discover Point Bonita's wild landscape,
geology and fascinating history. The
tunnel halfway to the lighthouse is open
only during visiting hours: Saturdays,
Sundays & Mondays 12:30 p.m. to 3:30
p.m.
Visiting the Marin Headlands
Public Transit:
Check out Transit 511.org for MUNI 76
Service on Sundays and holidays.
Driving Directions:
From the North
• Take Hwy 101 southbound.
• Exit at second Sausalito exit, just
before the Golden Gate Bridge.
• Bear right onto Alexander Avenue;
proceed back under the freeway.
• Follow Alexander Avenue 0.2-miles;
turn left onto Bunker Road.
From the South
• Take Hwy 101 northbound across the
Golden Gate Bridge.
• Exit Alexander Avenue; bear right.
• Follow Alexander Avenue 0.2-miles;
turn left onto Bunker Road.
Directions to Point Bonita Lighthouse
• On Bunker Road, pass through one way
Baker-BarryTunnel.
• Follow Bunker Road 3-miles; turn left
on Field Road.
• Follow Field Road 0.8-miles to Point
Bonita parking lot and trailhead.
• Walk the 0.5-mile trail to the
lighthouse.
For more information
Marin Headlands Visitor Center
Fort Barry, Building 948
Sausalito, CA 94965
(415) 331-1540
Point Bonita Then... With the discovery of gold in 1848, California
and the world changed forever. Soon, San
Francisco became the main port for gold seekers
from around the globe. In 1849, the city's
population leaped from 900 to 20,000!
To lead the new settlers and explorers safely
through the dangerous waters of the Bay
entrance, a system of lighthouses developed.
Alcatraz's light showed the way for ships
directly in front of the Golden Gate and Fort
Point's lighthouse marked the southern edge
of San Francisco Bay, but another lighthouse
was needed north of the Golden Gate to make
the entrance recognizable for ships sailing
up the coast from the south. That lighthouse
site became Point Bonita.
Point Bonita Lighthouse, the third lighthouse
on the West Coast, was completed in 1855.
Built upon a high ridge 300 feet above the
water, there were soon complaints that thick
fog frequently obscured the light beam. A
new site at a lower elevation was chosen nearby
at the tip of Point Bonita. Unstable rock
made construction of a hand-hewn tunnel
and trail to the site challenging. A new 3-room
brick structure was built to support the upper
half of the original lighthouse that was moved
to the new site in 1877.
Despite the effectiveness of the lighthouses,
over 300 boats ran aground near the Golden
Gate during the gold rush years. The worst
maritime disaster occurred in 1901, when the
steamer City of Rio de Janeiro struck Point
Diablo, near Point Bonita. Despite approaching
in darkness and continued fog, the pilot
was pressured by an influential passenger to
proceed. The lives of 128 passengers were lost
when the City of Rio de Janeiro struck rocks,
quickly filled with water and sank to the bottom
of the Bay. The pilot and the deceased
captain were later found guilt of gross neglegence
and the steamship companywas found
responsible for the heavy loss of life due to its
poorly supervised crew.
National Park Service
U.S. Department of the Interior
Marin Headlands
Golden Gate
National Recreation Area
Point Bonita Lighthouse
Al Greening
Originally built for a steam siren fog signal in 1874,
this structure was converted to a residence for the
lighthouse keeper in 1906, pictured here circa 1924.
SF Maritime NHP
Though the work was hard and
the hours long and lonely, many
lighthouse keepers, like Niles C.
Frey, Point Bonita Keeper, 2nd
Assistant and their wives still
managed to find time to raise
families.
(Photo circa 1896-1900.)
The City of Rio de Janeiro, built in 1878 and shown
here at anchor at Nagasaki, Japan, in 1894, belonged
to the Pacific Mail Steamship Company. In 1867, the
company began regular service between San Francisco
and Hong Kong.
Printed on recycled paper EXPERIENCE YOUR AMERICA www.nps.gov/goga
using soy-based ink
(rev. 05/05)
Visiting Point Bonita Directions to the Marin Headlands
From the North
• Take Hwy 101 southbound.
• Exit at second Sausalito exit, just before
the Golden Gate Bridge.
• Bear right onto Alexander Avenue;
proceed back under the freeway.
• Follow Alexander Avenue 0.2-miles;
turn left onto Bunker Road.
From the South
• Take Hwy 101 northbound across the
Golden Gate Bridge.
• Exit Alexander Avenue; bear right.
• Follow Alexander Avenue 0.2-miles; turn
left onto Bunker Road.
Directions to Point Bonita
• On Bunker Road, pass through one way
Baker-BarryTunnel.
• Follow Bunker Road 3-miles; turn left on
Field Road.
• Follow Field Road 0.8-miles to Point
Bonita parking lot and trailhead.
• Walk the 0.5-mile trail to the lighthouse.
For more information
Marin Headlands Visitor Center
Fort Barry, Building 948
Sausalito, CA 94965
(415) 331-1540
The Lighthouse Today Point Bonita today is part of the largest urban
national park in the United States, the Golden
Gate National Recreation Area. A secret jewel
of the Bay Area, Point Bonita is still an active
lighthouse. The U.S. Coast Guard maintains
the lighthouse and the National Park Service
provides access to visitors.
Point Bonita Lighthouse is reached by a halfmile
trail that is steep in parts. Discover Point
Bonita's wild landscape, geology and fascinating
history. The tunnel halfway to the
lighthouse is open only during visiting hours:
Saturdays, Sundays & Mondays 12:30 p.m. to
3:30 p.m.
The effectiveness of Point Bonita as an aid
to navigation depends on two factors: visibility
and acoustics. Visibility is provided by
a Fresnel lens, a light system developed by
French physicist Augustin Fresnel in 1822.
Fresnel's system works with ground glass
prisms arranged in rings around a light source.
His revolutionary invention bends 70% of
the outgoing bulb light and focuses it horizontally.
Seven types of lenses (or "orders")
were developed, each differing in size. Point
Bonita's second order lens sends its beam 18
miles across the water under clear conditions.
To reduce the immense cost of constructing
the Point Bonita lens, prisms were installed
only on the ocean side, not on the side facing
the cliffs. You may see the gap in the lens on
the cliff side while hiking down the Point
Bonita trail.
So that navigators can distinguish one
lighthouse from another, each has its own
pattern. Point Bonita's light switches on for
three seconds, off for one.
In dense fog, when the light signal cannot be
seen, a sound system comes into play.
Originallywarning cannon boomed out warnings
at Point Bonita. That cannon proved
ineffective and was replaced by a fog bell in
just four years. Later, about 1874, the first
steam siren was installed.
Today, an electric fog horn is used. Fog horns
are as distinctive as light signals. Point Bonita
sends out two blasts every 30 seconds. A fog
sensor triggers the fog signal. The lighthouse
projects a laserbeam outward. When water
droplets or dirt particles reflect off the beam,
the fog signal switches on or off.
The Lens & Fog Signal
Al Greening