Generally, if a United States coin doesn’t have a mint mark, it means it was struck at the Philadelphia Mint . This was the practice for most of US history, as the Philadelphia Mint was the original and primary mint, and mint marks were only added to coins produced at other branch mints (like Denver or San Francisco) to differentiate them.
However, there are some important exceptions to this general rule:
- 1965-1967: Coins minted during these years, regardless of where they were struck, do not have mint marks due to the Coinage Act of 1965, which temporarily eliminated them to discourage collecting during a coin shortage.
- West Point and San Francisco Minted Cents: During certain periods, the West Point and San Francisco Mints produced pennies for circulation without mint marks to prevent hoarding by collectors.
- Proof Coins: Some proof coins, especially those minted during the 1965-1967 period or those intended to be Philadelphia struck, might lack a mint mark, [according to APMEX] . Some error coins are also valuable if they lack a mint mark they were supposed to have.
It is important to note that not all coins without mint marks are rare or valuable . The vast majority of no-mint-mark coins found in circulation were struck at the Philadelphia Mint and are considered standard coinage.
What year did US coins not have mint marks?
Minting Without Mint Marks ( 1965–1967 )
From 1965 through 1967, no circulating U.S. coins had mint marks, regardless of where they were struck. This made it impossible to distinguish coins from Philadelphia, Denver, or San Francisco and was intended to eliminate collector-based hoarding.