1959 Map of Las Trampas Ridge

About this map

St Marys College and the surrounding hills of the Laguna de los Colorados land grant anchor this study of the East Bay interior. The map illustrates a transitional landscape where established ranching history meets mid-century suburban expansion, particularly visible in the growing communities of Lafayette and Alamo. The rugged spine of Las Trampas Ridge and Rocky Ridge separates the urbanizing corridors, preserving the wild character of Riley Canyon and the headwaters of Cull Creek. Extensive residential development is documented along the San Ramon Creek valley, supported by local institutions like Burton Sch and San Ramon Valley HS. To the south, the massive Upper San Leandro Reservoir dominates the drainage of the San Leandro Hills, while historical land divisions like the Arroyo de las Nueces y Bolbones continue to define the regional topography.