San Francisco Mint (S mint mark, 1854–present)
The San Francisco Mint was established in direct response to the California Gold Rush of 1849. The massive influx of gold from the Sierra Nevada and surrounding regions created an overwhelming need for a West Coast facility to convert raw gold into US coinage. Shipping gold across the continent to Philadelphia or by sea around Cape Horn was expensive, slow, and dangerous. On July 3, 1852, Congress authorized a branch mint in San Francisco, and coinage production began on April 15, 1854.
Early San Francisco Operations
The first San Francisco Mint occupied a modest commercial building on Commercial Street, quickly overwhelmed by the volume of gold brought in for coining. The second facility — the legendary "Granite Lady" at 5th and Mission streets (1874–1937) — was one of the most impressive buildings in the American West. Its massive granite construction famously survived the devastating 1906 San Francisco earthquake and fire, continuing operations while much of the city burned around it. Mint employees fought to save the building and its contents, and the Mint's vault of gold and silver provided critical financial resources for the city's recovery. The Granite Lady still stands today as a National Historic Landmark.
The current San Francisco Mint facility, opened in 1937, has evolved from a full-production mint into primarily a specialty facility. Today, San Francisco produces proof coins (the meticulously struck, mirror-finish collector coins sold by the US Mint), silver proof sets, and limited special-issue coins. San Francisco proof coins bear the "S" mint mark and are produced exclusively for collector sales, not for circulation.
Collecting San Francisco Coins
San Francisco coins span the full range of US numismatic history:
- Gold Rush-era coins (1854–1870s) — Early S-mint gold coins are highly collectible, with many dates featuring low mintages. The 1870-S half dime (unique or nearly so) is one of America's greatest rarities.
- Silver coinage (1850s–1955) — San Francisco produced silver coins for western commerce through the mid-20th century. Key dates include the 1909-S VDB cent, numerous Seated Liberty and Barber rarities, and scarce early Walking Liberty halves.
- Modern proofs (1968–present) — Since 1968, San Francisco has been the primary producer of proof coinage. S-mint proof sets are standard collector items.
Denver Mint (D mint mark, 1906–present)
The Denver Mint's history begins with the Colorado Gold Rush of 1858–1859, when gold was discovered at the confluence of Cherry Creek and the South Platte River near present-day Denver. The initial response was a private mint: Clark, Gruber & Company began striking gold coins in Denver in 1860 using local gold. The federal government purchased the Clark, Gruber facility in 1863 and operated it as an assay office — testing and valuing gold and silver — for over four decades.
Congress authorized the Denver Assay Office to begin coinage production in 1904, and the first Denver Mint coins were struck in 1906. The original neoclassical building, completed in 1906 with Colorado granite and Italian marble, remains in operation today as the Denver Mint's primary production facility — making it one of the oldest continuously operating mint buildings in the United States.
Denver's Role in Modern Coinage
Denver quickly grew into one of the two primary US Mint production facilities (alongside Philadelphia) responsible for producing the billions of circulation coins Americans use daily. Denver's annual production typically ranges from 5 to 8 billion coins, encompassing all circulating denominations: cents, nickels, dimes, quarters, half dollars, and dollar coins. All Denver coins bear the "D" mint mark.
Beyond circulation coinage, Denver also produces:
- Uncirculated Mint Sets — Denver contributes half the coins in annual US Mint uncirculated sets.
- Commemorative coins — Selected commemorative issues are struck at Denver.
- Bullion coins — Some American Eagle and American Buffalo bullion production occurs at Denver.
Note on the "D" mint mark: Prior to the Civil War, the "D" mint mark indicated the Dahlonega, Georgia mint (1838–1861). After Dahlonega's closure, the "D" was reassigned to Denver beginning in 1906. This dual usage means collectors must know the date to determine which mint a "D" coin came from: pre-1862 "D" = Dahlonega; 1906 and later "D" = Denver.
Collecting Denver Mint Coins
Key Denver coins include:
- 1916-D Mercury dime — Mintage of only 264,000, making it the key to the series ($1,000+ in Good condition).
- 1914-D Lincoln cent — A classic key date ($200+ in Good).
- 1927-D Saint-Gaudens double eagle — A significant gold rarity.
- D-mint Buffalo nickels — Several scarce dates including 1913-D Type 2 and 1921-S.
Visiting the Mints
Both the San Francisco and Denver Mints offer public tours (Denver's are free; San Francisco tours are limited). Watching modern coining presses stamp out thousands of coins per minute is a memorable experience for any collector. The Denver Mint tour is particularly popular and should be booked well in advance.
Up Next
West Point & Modern Minting — the newest mint facility and the future of US coinage.
This guide is for educational purposes. Where official standards, grading services, organization memberships, or legal requirements apply, consult the primary authority named in the references below or the relevant government agency.
Reviewed on March 2, 2026 by the US Coin Shows editorial team. Editorial policy
Frequently Asked Questions
What does the San Francisco Mint produce today?
San Francisco primarily strikes proof coins and special collector issues. All modern US proof coins bear the S mint mark.
What is the most valuable Denver Mint coin?
The 1916-D Mercury dime ($1,200+ in Good) is the most valuable regular-issue D-mint coin. The 1914-D Lincoln cent ($250+ in Good) and 1937-D 3-Legged Buffalo ($500+ in Good) are also highly valuable.
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