The sparsely populated Cajalco basin holds a rich and varied history. Native American pictographs, grinding slicks, and mortars dot the landscape, while mine shafts and tailings reflect the arduous labor of tin and gold miners in an earlier time. Except for these seekers of fortune, hermits, and the occasional rancher or sheepherder, there were few inhabitants in this region until Lawrence Holmes planted 50,000 carob trees in the 1920s and sold off plots to potential carob barons. Soon the valley boasted carob and citrus groves, homes, a school, and a store. The need for water in Los Angeles brought significant change to the valley when the Metropolitan Water Department constructed a terminus reservoir for the proposed Colorado River Aqueduct during the 1930s. This and many other events in the history of Lake Mathews and Gavilan Hills are illustrated here for the first time through 200 photographs, many never seen before by the public.