Battery Townsley

Soldiers inspecting Battery Townsley

Soldiers stationed at Battery Townsley located at Fort Cronkhite in the Marin Headlands.

PARC, Golden Gate National Recreation Area


Homeland Security of the 1930s

Battery Townsley was a casemated battery that mounted two 16-inch caliber guns, each capable of shooting a 2,100 pound projectile 25 miles out to sea. Completed in 1940, the guns and their associated ammunition magazines, power rooms, and crew quarters were covered by dozens of feet of concrete and earth to protect them from air and naval attack.

This battery, named in honor of Major General Clarence P. Townsley, a general officer in World War I, represented the zenith of American military technology and became the prototype for subsequent coastal defense batteries. As early as 1915, the army considered mounting the 16-inch guns to protect San Francisco, and by 1928, the War Department made the decision to construct two batteries, one on either side of the Golden Gate straits. Battery Townsley at Fort Cronkhite in Marin was finished first, followed several months later by Battery Davis at Fort Funston.

Successful Testing

By summer of 1940, Battery Townsley was ready for testing with live ammunition. Waiting for a non-foggy day in July took some patience, but finally, the fog cleared and several test shots were fired. As the mountain shock with the power of this incredible machine, a resounding roar was heard throughout San Francisco. The army calculated that the 16-inch guns' farthest range would be 25 miles out to sea, about the distance to the Farallon Islands. Battery Townsley, together with Battery Davis at Fort Funston on the coast south of the Golden Gate, became the prototypes for the army's future coastal defenses; the army planned to construct at least 25 additional 16-inch gun batteries along both the nation's eastern and western seaboards.

Top Secret

Battery Townsley was a high security operation; civilians living in San Francisco knew that there were batteries in the Marin Headlands but their exact locations were not revealed. A battery of Townsley's design had never been constructed, so the soldiers underwent several months of practice before holding firing practice for the first time. The men were subjected to endless drills, often under difficult situations: in the rain, in the pitch dark with all the electricity shut off, or with the roads blocked leading up from the barracks. Dealing with any contingency ensured that the soldiers could operate their guns at a moment's notice (and almost in their sleep) if ever under enemy attack. During World War II, over a hundred soldiers lived within the battery, ready to fire on five minutes warning. They fired Townsley's guns nearly 100 times each, but only in practice.


The growing threat of long-range bombers and nuclear weapons made Battery Townsley obsolete at the end of World War II. Its long-range guns, designed to shoot at battleships far at sea, were useless against aircraft flying at tens of thousands of feet. The big guns were scraped in late 1948, and the battery converted to use as a warehouse, temporary barracks, and underground test facility. Sealed for many years, the National Park Service began restoration work in 2006. Work continues to this day, carried out by a group of dedication Volunteers in Parks (VIPs).

Visiting Battery Townsley

Battery Townsley is now open to the public the 1st Sunday of the month, from 12 noon to 4 PM.

Battery Townsley is located one ½ mile up from the Fort Cronkhite parking lot, following the Coastal Trail; the walk up to the battery is strenuous so please allow at least 45 minutes. If you would like to request assistance to the site on open-to-the public days, please call the Marin Headlands Visitor Center at (415) 331-1540.

You can also visit the Marin Headlands page for more information about volunteering in the battery's preservation efforts, as well as directions and other programs and activities.

Big Battery Townsley News:

A New 16-in gun has arrived at Battery Townsley!

photo of Battery Townsley just after construction

Battery Townsley, just after construction, photo circa 1939

PARC, Golden Gate National Recreation Area

photo showing the construction of Battery Townsley

The construction of Battery Townsley in 1938 was a major engineering and construction undertaking. Building this battery required hundreds of men, thousands of tons of concrete and steel, and a small fleet of construction vehicles. In order to reach the designated site, the Army Corps of Engineers first had to clear and shape the site with dynamite and then pave a concrete road for the service vehicles. Photo circa 1938.

PARC, Golden Gate National Recreation Area

photo of soldiers loading Battery Townsley

Operating a 16-inch gun required a crew of  nearly 50 men. This photo shows soldiers loading a 2,100-pound projectile into the breech of one of the Townsley's gun.

PARC, Golden Gate National Recreation Area

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