Mint marks are letters that identify where a coin was made. In the past, they held the maker responsible for the quality of a coin. When the U.S. used precious metals such as gold and silver to make circulating coins, a commission evaluated the composition and quality of coins from each of the Mint facilities. These evaluations ensured that each facility produced coins to the correct specifications.
Philadelphia was the only branch in operation in the Mint’s earliest years, so identifying the source of a coin was not necessary. When the Mint opened branches in Charlotte, Dahlonega, and New Orleans in 1838, mint marks made their first appearance on U.S. coins.
However, the practice of not identifying Philadelphia’s coins continued even after the first branches were established.
This changed in 1942. When nickel was removed from five-cent coins during World War II, the “P” mint mark first appeared on coins produced in Philadelphia. The mark’s position also moved from the right of Monticello to above the dome to indicate the new metal composition.
After the war, when use of the regular alloy resumed, mint marks returned to their former positions, and the Mint no longer used Philadelphia’s “P.”
The Coinage Act of 1965 eliminated mint marks to discourage collecting while the Mint worked to meet the country’s coinage needs. So, no mint marks appeared on circulating coins from 1965 to 1967.
When mint marks returned in 1968, they were placed on the obverse, after having previously been on the reverse of coins.
In 1979, the Susan B. Anthony Dollar was introduced. Once again, the “P” mint mark appeared. The following year, the “P” appeared on all of the denominations except the cent, which still holds true today.
