The 1811/0 Overdate Large Cent is scarce in most grades, especially in high circulated grades. Compared to the Normal Date 1811, the Overdate appears to be at least three times as rare. Mint State 1811/0 Large Cents are exceedingly rare.
All 1811 Overdate Large Cents have a raised, horizontal mark below the E of ONE. This mark is visible even on low grade examples, even when the overdate has been worn down.