Large size legal tender note

A large-size Legal Tender Note, officially designated as a United States Note, is a form of fiat paper currency issued directly into circulation by the United States Treasury. Popularly known as a "greenback"—a title inherited from the earlier Demand Notes—the type was authorized under the First Legal Tender Act, which President Abraham Lincoln signed into law on 25 February 1862. The notes were introduced as fiat currency to meet the escalating financial obligations incurred by the Union government during the American Civil War after conventional taxation proved insufficient.

The introduction of legal tender paper money was proposed by Congressman Elbridge G. Spaulding as an emergency wartime measure after existing Demand Notes began to deteriorate in value. The initial legislation sanctioned $150 million of currency, using the new notes to replace the $5, $10, and $20 Demand Notes whilst also introducing entirely new designs in denominations of $50, $100, $500, and $1,000. Over the following decades, the statutes governing these notes were amended repeatedly, resulting in numerous series and a broad variety of denominations being issued across the large-size era prior to 1929.

In physical appearance, large-size United States Notes differ dramatically from modern small-size American currency. Early issues shared a very similar obverse layout with earlier Demand Notes, but the phrase "On Demand" was omitted in favour of the explicit inscription "This Note is a Legal Tender". On the reverse, early 1860s notes carried the second obligation, defining the currency as legal tender for all debts public and private, excluding import duties and interest on the public debt. Although not backed by gold reserves, bank deposits, or government funds, the notes were receivable by the government at par for short-term deposits and twenty-year bonds.

It can be distinguished from earlier Demand Notes by the absence of the promise to pay "On Demand", and from later small-size issues by its distinct early pictorial design rather than modern standardised styling with red Treasury seals.