These days, “protecting the San Francisco Bay” usually refers to improving water quality, restoring wetlands, or controlling invasive species. But for most of the 20th century, San Francisco Bay was America’s most valuable Pacific port, and the US Government and military invested an enormous amount of time and money building defenses against a feared enemy attack from the sea and air.
Development of coastal defenses around the entrance to San Francisco Bay has been continuous since the first Spanish army soldiers came to the Presidio. As armaments developed greater range and power, gun placements and batteries were built to the north and south of the Golden Gate. Today, Golden Gate National Recreation Area is dotted with the remains of these coastal fortifications and military sites from Fort Funston in the south to Battery Townsley in the Marin Headlands. Some have been preserved and restored for visitors, while others wait quietly for a hiker to find them and pause to imagine the soldiers who once stood guard here, scanning the Pacific Ocean for incoming ships and warplanes.
When news reached San Francisco of the Japanese attack on Pearl Harbor in December 1941, people were certain that a military invasion of the mainland was imminent. Every military site was on full alert, and every beach was strung with barbed wire and patrolled by armed soldiers. Rumors circulated among panicky civilians about Japanese fleets off the coast of California, and even of actual Japanese landings. Prejudice against Japanese Americans took a dark turn, and rumors began that Japanese fishermen were mining harbors; or that Japanese farmers were poisoning produce. These fears were used to justify the forced removal and incarceration of Japanese Americans living in coastal areas for the duration of the war.
The feared invasion never materialized, but all around the Bay Area, the military ratcheted up industrial production of ships, aircraft and artillery for the war. Nearly 250,000 people were employed by Bay Area shipyards. 1.6 million soldiers, sailors, Marines, and civilians boarded ships at Fort Mason bound for the war in the Pacific. The wartime population boom, and resulting demand for transportation, water, housing, and other services, profoundly changed Bay Area cities into the urban centers we know today.
The nerve center for all of this activity was the Presidio – in particular an underground facility at Fort Winfield Scott called the Harbor Defense Command Post/Harbor Entrance Command Post (HDCP/HECP), where army and navy senior staff coordinated resources to defend the Bay and deploy ships and materials through the Golden Gate. By 1944, military planners considered an attack on the harbor unlikely, and began to phase out the defensive operations at the Presidio. After the war with Japan ended, advances in long-range and nuclear weaponry rendered much of the Army’s fixed defense positions obsolete. The unanticipated but happy legacy of this era is the extensive open spaces overlooking the Golden Gate and nearby coastline. These former US Army lands are now the heart of a spectacular urban park providing welcome recreational opportunities for visitors and residents alike.