The mint act of April 2, 1792, made is possible to mint the smallest denomination US coin ever produced. Minting started in 1793. The coins were not particularly popular with the public. They were minted until 1856 when the large cent and the half cent were replaced by the new smaller copper-nickel cent.
After these coins were removed from circulation they became very popular with numismatists and have been sought after by collectors ever since the 1850's. With the small production numbers originally these coins are rather scarce and are quite fun to collect, not only because of their unique denomination but also because of their early American history.