The "S" Mint Mark: San Francisco's Tiny Signature on US Coins

It's a tiny "S." That's it. But the details matter.

Where to Look

• Pre-1968: Reverse (tails), bottom center (Lincoln cent, Jefferson nickel, Roosevelt dime, Washington quarter, Franklin/Kennedy half).
• 1968–present: Obverse (heads), lower right (near date) on most circulating coins.
• Proof/Modern Commemoratives: Often obverse, but varies by design.

History

• 1854: San Francisco Mint opens (Gold Rush).
• 1854–1955: Circulating coinage (gold, silver, base).
• 1955–1965: Closed (coin shortage reversed this).
• 1968–present: Proof sets, commemoratives, bullion (Silver/Gold Eagles), some circulating (S-mint quarters 2012+).

Why It Matters

• Proof coins: "S" = proof finish (mirror fields, frosted devices) — collector premium.
• Rarities: 1909-S VDB cent, 1916-D (wait, Denver) — 1916-S Mercury dime, 1932-S Washington quarter, 1955-S Franklin half.
• No "S" proof errors: 1968–1974 proof dimes/quarters/halves missing "S" = $500–5,000+.

Authentication

Counterfeit "S" marks exist on key dates. Buy slabbed (PCGS/NGC) or learn diagnostics (mint mark style, die markers).

One letter. Two centuries. A lot of value hiding in plain sight.