San Andreas is one of classic communities of the western Sierra Nevada Mountains and is the present Calaveras County seat. San Andreas is traversed by California State Route 49 which is known as the Golden Chain Highway. Modern California State Route 49 currently passes through San Andreas via a bypass of downtown on Charles Street. Prior to the current bypass alignment being constructed California State Route 49 passed through San Andreas via Main Street and Gold Strike Road. The difference between the modern alignment California State Route 49 and the original can be seen on this map illustration below.
Part 1; the history of California State Route 49 in San Andreas
San Andreas was founded by Mexican Miners during 1848 and was named after Andrew the Apostle. San Andreas was initially largely based around placer claims which were quickly exhausted during the early California Gold Rush. A large gold vein was discovered in an underground stream during 1853 which led to San Andreas being formally plotted as a town and spurred a mining boom. Post Office service in San Andreas began in 1854 and has not shuttered since. The mining boom in San Andreas was so substantial that the town was rebuilt after fires in 1858 and 1863. San Andreas became the Calaveras County seat in 1866 and has retained it to modern times despite not being an incorporated city.
San Andreas can be seen during the prime of the community on the 1873 Bancroft's Map of California, Nevada, Utah and Arizona.
Below is the historic plaque regarding the history of San Andreas which can be found at the southwest corner of Main Street and Charles Street.
From modern California State Route 49 southbound signage approaching Gold Strike Road indicates it is Historic California State Route 49. California State Route 49 is the only Sign State Route in California with formally signed Historic corridors. Other Historic California State Route 49 corridors can be found in Mokelumne Hill, Sutter Creek and Amador City.