Placer County, California — Issued by the State Mining Bureau

Cartographer: Compiled under Lewis E. Aubury, State Mineralogist, State Mining Bureau, San Francisco, with field work by H. G. Riling, W. W. Bradley, Waldemar Lindgren, and John B. Prater (ca. 1903)

Year: 1902

This county-wide sheet plots every patented and active mine in vivid red against a one-mile public-land grid. Black hachured lines trace the American River and its gold-bearing tributaries, while wagon roads and the Southern Pacific’s Sierra grade thread northeast toward Donner Pass. Township and range numbers are lettered across the foothills, guiding prospectors to exact legal descriptions. Concentrations of red dots around Auburn, Dutch Flat, and Foresthill reveal the heart of the quartz- and hydraulic-gold belt, whereas the western valley floor shows only scattered gravel pits. The map was published in the bureau’s Forty-Fourth Report to help investors compare mineral districts and to aid county assessors in taxing mining properties.