Instructions
Inspect the reverse of the coin. The mint mark is located below the wreath and above the words "One Dollar."
Know that if you do not see a mint mark in this location, it means the U.S. Mint in Philadelphia struck the coin. Many American coins struck there do not have a mint mark.
Look for a letter that represents which mint struck the coin. Each U.S. Mint, other than the Philadelphia mint, struck a corresponding letter on any Morgan silver dollars that were coined there. An "O" represents New Orleans, "CC" is for Carson City, "D" is for Denver and "S" is for San Francisco.
Search for error coins. A handful of Morgan silver dollars were mis-struck at certain mints. For example, some copies of the 1880 dollar from the Carson City mint have the number 80 struck over 79 or 8 over 7 to correct initial errors in the date. The 1888 dollar from the New Orleans mint features a double-die front in which part of Liberty's face was struck twice, making the lips especially prominent. These errors can fetch premiums among numismatists, or coin collectors.