The 1856-O Dime has a large mintage of over a million pieces but, like many of the New Orleans mint issues of this period, it is hard to find in high grade. PCGS has certified fewer than two dozen Mint State examples of this date, most of which are MS64. The typical 1856-O Dime is well-struck, though the occasional example may show weakness on some of the denticles. The finest known 1856-O Dime is a single PCGS MS-66.
The mintmarks on this date appear in two different sizes: Medium O and Large O. Of the nine die varieties described by Jerry Fortin, three have repunched dates.