1959 Map of Briones Valley

About this map

Briones Reservoir and San Pablo Reservoir dominate the center of this map, illustrating the critical role of water infrastructure in the mid-century development of Contra Costa County. This 1959 survey, updated with 1968 aerial data, shows the rapid expansion of suburban residential zones in purple around Orinda and Lafayette, encroaching on the once-rural character of La Boca de la Cañada del Pinole. The landscape is a network of ridges, including Oursan Ridge and Sobrante Ridge, which define the valley floors where older landmarks like the Briones Valley School and the Mokelumne Aqueduct persist. The northern edge reveals the industrial and transport corridor near Martinez, where the Atchison Topeka and Santa Fe railroad skirts Franklin Canyon. The transition from open range to master-planned communities is evident in the layout of the Orinda Country Club and the preservation of Charles Lee Tilden Regional Park.