Today four mints operate in the United States producing billions of coins each year. The main mint is the Philadelphia Mint, which produces circulating coinage, mint sets and some commemorative coins. The Denver Mint also produces circulating coinage, mint sets and commemoratives. The San Francisco Mint produces regular and silver proof coinage, and produced circulating coinage until the 1970s. The West Point Mint produces bullion coinage (including proofs). Philadelphia and Denver produce the dies used at all of the mints. The proof and mint sets are manufactured each year and contain examples of all of the year’s circulating coins.
The producing mint of each coin may be easily identified, as most coins bear a mint mark. The identifying letter of the mint can be found on the front side of most coins, and is often placed near the year. Unmarked coins are issued by the Philadelphia mint. Among marked coins, Philadelphia coins bear a letter P, Denver coins bear a letter D, San Francisco coins bear a letter S, New Orleans coins bear a letter O and West Point coins bear a letter W. S and W coins are rarely, if ever, found in general circulation, although S coins bearing dates prior to the mid-1970s are in circulation. CC and D mint marks were used for a short time in the early-to-mid-nineteenth century by temporary mints in Carson City, Nevada and Dahlonega, Georgia, respectively; all such coins are now in the hands of collectors and museums.