To process the gold and silver being mined in new locations, the federal government passed legislation to open three new branch mints in 1835: in Charlotte, North Carolina; Dahlonega, Georgia; and New Orleans, Louisiana. The first two would only strike coins from local gold. The third would mint coins from silver as well as from gold, because those two metals were pouring into the Crescent City from Latin America.
All three branch facilities opened their doors in 1838. The New Orleans Mint was a success from the very beginning. The other two suffered growing pains but finally reached full production in the 1850s. All three closed during the Civil War, but New Orleans eventually reopened in 1879 and remained a major player in the country's monetary system until the first decade of the twentieth century. Charlotte and Dahlonega stayed closed.
A way was sought to distinguish the products of these new mints from those of the original one. Philadelphia had never marked its coins-there had been no need, with no other coiners in existence. But now a way was devised to show which coins came from where.
A mint mark, consisting of a single letter, would be placed on each of the products of the branch Mints-an O for New Orleans, a D for Dahlonega, and a C for Charlotte. The mint marks briefly appeared on the coins' obverse, but then they were relegated to the reverse, where they remained.
Collectors call the 1838 Charlotte half eagle a "one-year type": coins of this design with the obverse mint mark were only struck during that single year. There were about seventeen thousand of them, compared with over a quarter million at Philadelphia.