Originally constructed in 1816 by Father José Mara de Zalvidea of the Mission San Gabriel Arcángel, El Molino Viejo (or The Old Mill) is a historic grist mill in the San Rafael Hills of modern-day San Marino, California, United States (San Gabriel Mission). As one of the original ten locations in Los Angeles County to be added to the National Register of Historic Places in 1971, this building holds the distinction of being Southern California’s oldest commercial structure. California has recognized the Old Mill as a historical landmark as well.
The San Gabriel Mission was established in 1816, according to its records, while several sources give different years for its construction. Franciscan Father José Maria de Zalvidea, who was in charge of the San Gabriel Mission at the time, planned the mill that was constructed on mission property. Indian workers from the Tongvan Mission, led by Father Zalvidea, constructed it.
This mill looks like it may have been a stronghold. Its foundation is about five feet thick, with walls constructed from brick and volcanic tuff. In the event of “a commotion among their somewhat hesitant converts,” the huge fortress-like walls were designed to protect the padres, according to some accounts. The upper walls are constructed from sun-dried adobe slabs, and a lime mortar derived from burned sea shells covers the exterior. Large buttresses, which can still be seen at the building’s outside corners, provide additional support for the pine and sycamore beams that are linked together with leather thongs.
El Molino Viejo, located near Alhambra area, is the oldest commercial structure in Southern California, making it a significant historical landmark in both California and the United States. The building was registered by the Historic American Buildings Survey in 1937. In 1971, it was recognized as one of the first ten Los Angeles County locations to be added to the National Register of Historic Places. Additionally, it is a California Historical Landmark.