The dual banking system - 1860s
In 1863, Congress passed the National Bank Act in an attempt to retire the greenbacks that it had issued to finance the North's effort in the American Civil War. This opened up an option for chartering banks nationally. As an additional incentive for banks to submit to Federal supervision, in 1865 Congress began taxing any issue of state bank notes (also called "bills of credit" or "scrip") a standard rate of 10%, which encouraged many state banks to become national ones. This tax also gave rise to another response by state banks -- the invention of the demand deposit account, also known as a checking account. By the 1880s, deposit accounts had changed the primary source of revenue for many banks. The result of these events is what is known as the "dual banking system." New banks may choose either state or national charters (a bank also can convert its charter from one to the other).
National Banks, are the bank that have the word "National" or "N.A." in the name of the bank (i.e. First National Bank, or Citibank N.A.) National Banks are regulated by the Office of the Comptroller of the Currency, Department of the Treasury.