About San Andreas CDP, California
San Andreas is a census-designated place (CDP) in Calaveras County, California, United States. The population was 2,783 at the 2010 census. It is the county seat of Calaveras County. The town is located on State Route 49 and is registered as California Historical Landmark #252.
The town of San Andreas sprang up almost overnight in 1848. It was founded by Mexican miners who had been working in the area since 1846, and named after Saint Andrew, the patron saint of Spain. The miners quickly organized a town, with streets, a central plaza, and a church. A hotel and store soon followed.
The town grew rapidly during the Gold Rush, reaching a population of over 5,000 by 1852. It was the largest town in the county and served as its seat of government. However, as the gold mines began to play out in the 1850s, the population started to decline. By 1860, it had fallen to just 1,000 people.
San Andreas remained the county seat after the Gold Rush ended, but its population continued to decline. It reached a low point of just 400 people in 1900. However, it has since begun to rebound, and now has a population of over 2,700.