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Listing of Mint marks
Mark.............. Mint.........................................Date of operation
P= (or none)=...... Philadelphia, Pa.............................. 1793-present
C=.....................Charlotte, N.C., (gold coins only)........1838-1861
D=.................... Dahlonega, Ga. (gold coins only).........1838-1861
O=....................New Orleans, La..............1838-1861; 1879-1909
S=.................... San Francisco, Calif..........1854-1955; 1968-present
CC=.................. Carson City, Nev..............................1870-1893
D=.................... Denver, Colo....................................1906-present
W=................... West Point, N.Y...............................1976-present


A Mint mark is a letter or letters indicating what specific Mint struck a coin. For example, a coin struck at the Denver Mint will generally bear a D Mint mark.

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On US coinage minted in the past 100 years, here are the locations of the mint marks....

Lincoln Wheat Cent - Obverse (front) below the date.
Lincoln Memorial Cent - Obverst below the date.
Liberty-Shield Nickel - Reverse (back) toward the edge at 7 o'clock under the dot separating United and Cents.
Buffalo Nickel - Reverse below five cents.
Jefferson Nickel - Reverse to the right of Monticello (Small Mint Mark-SMM).
Jefferson Wartime Nickel - Reverse above Monticello (Large Mint Mark-LMM).
Barber Dime - Reverse below the wreath at 6 o'clock.
Mercury Dime - Reverse to the right of "One" (One Dime).
Roosevelt Dime - Reverse above the "E" in "One".
Barber Quarter - Reverse between Quarter and Dollar and below the eagle.
Standing Liberty Quarter - Obverse SMM just to the left of the date.
Washington Quarter (32-64) - Reverse above the R in quarter.
Washington Quarter (68-present) - Obverse lower right from Washington head.
Barber Half - Reverse below the eagle, above the D in dollar.
Walking Liberty Half (16-17) - Obverse below the motto.
Walking Liberty Half (18-47) - Reverse at 8 o'clock beneath the rock the eagle is standing on.
Franklin Half - Reverse above the bell
Kennedy Half (64) - Reverse below the olive branch in the left talon.
Kennedy Hald (68-present) - Obverse below Kennedy's head.
Morgan Dollars - Reverse below the wreath and between D and O in Dollar.
Peace Dollar - Reverse at 8 o'clock, left of the tail feathers.
Eisenhower Dollars - Obverse below the head.
Susan B Anthony Dollars - Obverse on SBA's right (our left) shoulder.
Sacagawea Dollar - Obverse below the date.

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