Separately issued unfolded map of Placer County, published by C.F. Weber.
The map shows early railroads, roads, wagon roads, mines, lakes, mills, and many other details.
Placer County was one of the earliest counties to be formed after the original California Counties. Only three years after the discovery of gold, the fast-growing county was formed from portions of Sutter and Yuba counties on April 25, 1851 with Auburn as the county seat.
Placer County took its name from the Spanish word for sand or gravel deposits containing gold. Miners washed away the gravel, leaving the heavier gold, in a process known as "placer mining."