1961 Map of Calaveras Reservoir

About this map

Urban expansion from Milpitas and the Berryessa district pushes into the foothills of the Diablo Range on this 1961 survey, which includes updates through 1980. The contrast between the dense residential development and the sprawling industrial zones of the Santa Clara Valley and the steep, undeveloped terrain to the east is starkly visible. This documentation by the Geological Survey tracks the rapid conversion of agricultural lands into suburban neighborhoods, particularly along the southern and western edges of the sheet. The rugged topography rising toward the northeast serves as a natural barrier to this mid-century growth, preserving the watershed around the prominent central reservoir and the various creeks that drain into the valley floor. These purple-tinted revisions provide a clear record of where the South Bay's post-war housing boom met the constraints of the coastal mountains.