From the mission days of the 1770’s to the mid-1800’s, adobe structures were the dominant building style. The clay soil of San Luis Obispo County is well adapted to the manufacture of adobe bricks and under the tutelage of Spanish Missionaries, the Chumash Indians became skilled adobe craftsmen. Unfortunately, the local climate with its moist coastal influence and seasonal freezing and thawing caused many of the adobe structures to crumble. With the arrival of the Pacific Coast Railway in the late 1870’s, wood became readily available and replaced adobe as the primary building material. As wood replaced adobe brick, the architecture and style of buildings changed in San Luis Obispo. The photographs of the Historical Adobes of San Luis Obispo County were taken in 1962. Some of the buildings no longer exist. Identifications were made as well as possible from existing information.