Both United States Notes and Federal Reserve Notes are parts of our national currency and both are legal tender. They circulate as money in the same way. However, the issuing authority for them comes from different statutes. United States Notes were redeemable in gold until 1933, when the United States abandoned the gold standard. Since then, both currencies have served essentially the same purpose, and have had the same value. Because United States Notes serve no function that is not already adequately served by Federal Reserve Notes, their issuance was discontinued, and none have been placed in to circulation since January 21, 1971.
The Federal Reserve Act of 1913 authorized the production and circulation of Federal Reserve notes. Although the Bureau of Engraving and Printing (BEP) prints these notes, they move into circulation through the Federal Reserve System. They are obligations of both the Federal Reserve System and the United States Government. On Federal Reserve notes, the seals and serial numbers appear in green.
United States notes serve no function that is not already adequately served by Federal Reserve notes. As a result, the Treasury Department stopped issuing United States notes, and none have been placed into circulation since January 21, 1971.