After producing over two million Dimes in 1842, the employees at the New Orleans Mint took a bit of a breather and struck only 150,000 Dimes in 1843. This was a foreshadowing of things to come, as production of Dimes at New orleans either stayed low or didn't occur at all in many of the years during the 1840's.
With such a small mintage, the 1843-O Dime is a very popular coin. Circulated examples are not common, but they are relatively inexpensive in grades below Extemely Fine. In Mint State, the 1843-O Dime is very rare. We know of only four examples, and but two of these have been graded by PCGS. The best 1843-O Dime appears to be the Eliasberg example, which we list in the PCGS CoinFacts Condition Census as MS66 (estimated grade).