<P> The history of the United States Dollar refers to more than 240 years since the Continental Congress of the United States authorized the issuance of Continental Currency in 1775 . On April 2, 1792, the United States Congress created the United States dollar as the country's standard unit of money . The term dollar had already been in common usage since the colonial period when it referred to eight - real coin (Spanish dollar) used by the Spanish throughout New Spain . </P> <P> By the end of 1778, Continental Currency retained only between ​ ⁄ to ​ ⁄ of its original face value . By 1780, Continental bills--or Continentals--were worth just ​ ⁄ of their face value . Congress tried to reform the currency by removing the old bills from circulation and issuing new ones, but this met with little to no success . By May 1781, Continentals had become so worthless they ceased to circulate as money . Benjamin Franklin noted that the depreciation of the currency had, in effect, acted as a tax to pay for the war . In the 1790s, after the ratification of the United States Constitution, Continentals could be exchanged for treasury bonds at 1% of face value . </P>

Establishment of a single national currency in the u.s. did not take place until