The San Francisco branch, opened in 1854 to serve the goldfields of the California Gold Rush, uses an S mint mark. It quickly outgrew its first building and moved into a new facility in 1874. This building, one of the few that survived the great earthquake and fire of 1906, served until 1937, when the present facility was opened. It was closed in 1955, then reopened a decade later during the coin shortage of the mid-60s. In 1968, it took over most proof-coinage production from Philadelphia, and since 1975, it has been used almost exclusively for proof coinage, with the exceptions of the Anthony dollar (1979–1981), a portion of the mintage of cents in the early 1980s, (these cents are indistinguishable from those minted at Philadelphia), and a small portion of America the Beautiful quarters minted in circulation-quality (but not issued for circulation) since 2012.;
