There have long been stories of two “lost” Missions in California and in the last few decades these have been given identities: Mission San Pedro y San Pablo de Bicuñer and Mission La Purisima Concepción de la Virgén Santisima. The word lost is in quotes because the location of the Mission La Purisima Concepción has always been known, the Mission building simply no longer exists.
The location of San Pedro y San Pablo de Bicuñer, on the other hand, was lost to the mists of time until the 1970s when a man named Richard Yates spent years trolling through historical records and personal accounts to determine the exact location of the Mission. In his article, Locating the Colorado River Mission San Pedro y San Pablo de Bicuñer from The Journal of Arizona History (Vol. 13, No. 2 (Summer 1972)) he puts the Mission’s location close to Laguna Dam on the California side of the Colorado River. Previous to this, scholars believed the location was west in an area called Pilot Knob.
The location of this Spanish Mission is well off the beaten path. In fact, without GPS coordinates (32°48’59″N 114°30’54″W) it would be difficult to find unless you were local and knew which backroad farm routes and secret hidden dirt roads to take. There are no ruins at the location; only a plaque and altered landscape marks the spot.
The lifespan of this Mission was short-lived. It was built in 1781 to protect the Anza Trail crossing of the Colorado River. Six months after the Mission’s founding, the Quechan peoples attacked the Mission and burned it to the ground. This cut off the ability to cross the river and eliminated Spanish communications between Mexico and Alta California.
The Spanish never rebuilt the Mission.
There is some debate as to whether is this one of the “California Missions” or one of the “Arizona Missions.” Part of the confusion is because much of the Spanish historical documentation itself is vague and some records place the Mission on the California side of the river… and others on the Arizona side. The location of the plaque is on the California side of the river, but you access the area from Arizona.
Historically, Mission San Pedro y San Pablo was administered as a part of the Arizona mission chain… but now no one is really claiming it as their own; it is, however, listed as a California Historical Landmark.