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Alcatraz Island Lighthouse

Fl W 5s🇺🇸Northern California, USOperational

Location & Light Range

About Alcatraz Island Lighthouse

Also known as: United States Coast Guard Lighthouse

The Alcatraz Island Lighthouse, built in 1854, stands 26 meters tall with its light positioned 65 meters above sea level. Originally constructed on Alcatraz Island in San Francisco Bay, this light station predates other facilities on the island. It served the bay during the island's periods as a military installation and prison. A second, taller concrete tower was erected in 1909 near the original structure, which was later demolished following earthquake damage. The lighthouse was automated in 1963, the same year the federal penitentiary closed.

Why it matters: This lighthouse is a National Register of Historic Places contributing property and is part of the museum on Alcatraz Island.

Background
Alcatraz Island Lighthouse is a lighthouse—the first one built on the U.S. West Coast—located on Alcatraz Island in California's San Francisco Bay. It is located at the southern end of the island near the entrance to the prison. The first light house on the island was completed in 1854, and served the bay during its time as a Citadel and military prison. It was replaced by a taller (95 feet (29 m) above mean sea level) concrete tower built in 1909 to the south of the original one which was demolished after it was damaged due to earthquake in 1906. The automation of the lighthouse with a modern beacon took place in 1963, the year Alcatraz closed as the Alcatraz Federal Penitentiary. It is the oldest light station on the island with a modern beacon and is part of the museum on the island. Although when viewed from afar it easily looks the tallest structure on Alcatraz, it is actually shorter than the Alcatraz Water Tower, but as it lies on higher ground it looks much taller.

Light & Optic

Characteristic Signature
Fl W 5s
Flash Type
Flashing
Light Color
White
Flash Count
1 flash
Interval
5s
Focal Height
65m

Construction & History

Year Built
1854
Heritage Status
National Register of Historic Places contributing property

References & Identifiers

Wikipedia
Read on Wikipedia →
Wikidata
Q4712967 →
OpenStreetMap
View on OSM →

Tower & Structure

Tower Height
26m

Location

City
Northern California
Country
🇺🇸US
Latitude
37.8262°
Longitude
-122.4222°

Nearby Vessels

Flag
Type
Name
Dist.
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Frequently Asked Questions

How do mariners identify Alcatraz Island Lighthouse at night?+
Alcatraz Island displays the characteristic Fl W 5s — 1 white flash every 5 seconds. Each lighthouse has a unique flash pattern published in the List of Lights, allowing mariners to positively identify it and distinguish it from other navigation aids in the area.
Which ports and harbors does Alcatraz Island Lighthouse guide vessels into?+
Alcatraz Island Lighthouse assists vessels approaching 5 nearby ports. The closest is TREASURE ISLAND at 2.4 NM to the E. Other ports served include TRAVIS (2.6 NM W), Sausalito (3.2 NM NW), Tiburon (3.2 NM NNW), San Francisco (3.4 NM SSE). Mariners should consult the relevant chart for full approach and pilotage information.
Is Alcatraz Island Lighthouse still active and maintained?+
Yes, Alcatraz Island Lighthouse is currently operational. It is actively maintained and continues to emit its characteristic light signal for marine navigation. Most modern lighthouses are automated and monitored remotely by the national maritime authority.
What shipping routes pass near Alcatraz Island Lighthouse?+
Alcatraz Island Lighthouse is located within the US West Coast shipping lane — a major trans-Pacific trade route serving West Coast ports of the United States. This makes it an important navigation reference for commercial shipping traffic in the region.
How can I track vessels near Alcatraz Island Lighthouse?+
You can track vessels near Alcatraz Island Lighthouse in real time using MarineRadar. The platform shows live AIS positions of ships in the area, including vessel name, type, flag, speed, and course. Use the "Track Vessels Nearby" button on this page to open the live map centered on this lighthouse.