Everybody makes mistakes and the United States Mints are no exception.  The odds of producing billions of coins each year with no errors is simply too great.  Normally, error coins are caught through the usual quality control procedures but, occasionally, some of the mistakes get by the inspectors and enter the normal channels of circulation.  Some error coins may have been made deliberately, as their very existence is cause for suspicion.

The categories at right feature some of the most dramatic and important error coins that have ever appeared on the market.