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1931 Map of Pentland Junction

Name: 1931 Topographic Map of Pentland Junction
Creator: U.S. Geological Survey
Published: 1931
License: https://creativecommons.org/publicdomain/mark/1.0/

USGS Topo · Published 1931

About this map

Oil infrastructure and industrial expansion dominate the landscape of the southern San Joaquin Valley in the early 1930s. The convergence of the Southern Pacific railroad at Pentland Junction serves as the focal point for a network of refineries and pumping stations scattered across Maricopa Flat. The map documents a specific era of petroleum production, detailing the operations of the Richfield Refining Plant No. 71, Lakeview Refining Co., and the Associated Oil Co. near the base of the surrounding hills.

Residential life is closely tied to these industrial sites, as seen in worker settlements like Essex Camp and the Western Mineral Camp. Beyond the derrick-dotted plains, the survey captures the intersection of the Mt Diablo Base and Meridian and the San Bernardino Base and Meridian, a critical point for California land surveying. The presence of numerous wells and specialized facilities like the General Petroleum Corporation Pentland Pumping Sta. illustrates the density of the region's energy economy before mid-century changes altered the terrain.