Mint Mark Definition
A mint mark is a letter or other symbol that identifies the mint at which a given coin has been made. On most U.S. coins, the mint mark will be a D (for the Denver mint), or an S (for San Francisco.) Sometimes P was used (for Philadelphia), and other marks for historical issues (such as CC for Carson City.) The positions of the mint marks on some of the currently circulating U.S. coins are given below, but keep in mind that if the mint mark is absent, the coin was minted at Philadelphia.
The Philadephia mint mark is often omitted.
Example Mint Mark Locations
On the Jefferson Nickel since 1968, the mint mark follows the date on the obverse.
On the Roosevelt Dime since 1968, the mint mark is right above the date on the obverse.
On the Statehood Quarter, the mint mark is just below "In God We Trust" on the obverse.
History of Mint Marks
Originally, mint marks were added to coins to indicate the coining facility that produce the coin in case there were any problems with the coin's metallic composition. In the early days of The United States Mint coining facilities were located where coins were needed the most and raw material was most plentiful.
The main coining facility for The United States Mint is located in Philadelphia, Pennsylvania and began production in 1793.
Subsequently, the United States Mint opened the following facilities:
Dates of Coining Operation
Mint Mark Used
1793 - Present
P or Nothing
New Orleans, Louisiana
1838 - 1909
1838 - 1861
Charlotte, North Carolina
1837 - 1861
San Francisco, California
1854 - Present
Carson City, Nevada
1870 - 1893
1906 - Present
West Point, New York
1984 - Present
Annually each mint facility would send a sample of their coins to the mint headquarters. There they would be assayed by a panel of inspectors. Each coin would be measured to ensure proper diameter and thickness. Additionally, the coins were weighed to make sure they contained the proper amount of precious metal. Finally, the coins were chemically tested to ensure that the proper fineness of precious metal was correct.
If there was a problem with any of the coins, the inspectors would know which mint facility produced it. Then an investigation could be launched to see why the mint facility in question was producing coins that were not measuring up to proper specifications. This was important in prior years because coins were made with precious metal and people valued the coins based upon the amount of precious metal and the coin.
Currently, since circulating United States coinage contains no precious metal, the mint marks are more of a matter of tradition then quality control.
Edited by: James Bucki