Mint Marks: Those Small Letters On U.S. Coins Explained

What are mint marks? Mintmarks are small letters stamped on U.S. coins that designate where the coin was made. Where a coin was minted affects its value. See which coins each U.S Mint facility made. And what a U.S. coin without a mintmark means. (Some are rare error coins. Others are not supposed to have a mint mark.)