Banknotes of U.S. dollar

The U.S. Constitution provides that Congress shall have the power to " borrow money on the credit of the United States".Congress has excercised that power by authorizing twelve private companies —the Federal Reserve Banks—to issue Federal Reserve Notes. Those notes are "obligations of the United States" and "shall be redeemed in lawful money on demand at the Treasury Department of the United States, in the city of Washington, District of Columbia, or at any Federal Reserve bank." Federal Reserve Notes are designated by law as "legal tender" for the payment of debts. Congress has also authorized the issuance of more than 10 other types of banknotes, including the United States Note and the Federal Reserve Bank Note. The Federal Reserve Note is the only type that remains in circulation since the 1970s.

The largest denominations of currency currently printed or minted by the United States are the $100 bill and the $100 one troy ounce Platinum Eagle.

$1 and $2 color: White and rich gray
$5 color: Gray and some purple
$10 color: Light yellow
$20 color: Light green
$50 color: Deep blue and purple
$100 color: Rich light blue (Series 2009 redesign is scheduled for release on February 10, 2011)
Currently printed denominations are $1, $2, $5, $10, $20, $50, and $100. Notes above the $100 denomination ceased being printed in 1946 and were officially withdrawn from circulation in 1969. These notes were used primarily in inter-bank transactions or by organized crime; it was the latter usage that prompted President Richard Nixon to issue an executive order in 1969 halting their use. With the advent of electronic banking, they became less necessary. Notes in denominations of $500, $1,000, $5,000, $10,000, and $100,000 were all produced at one time; see large denomination bills in U.S. currency for details. These notes are now collector's items and are worth more than their face value to collectors.

The design of the notes has been accused of being unfriendly to the visually impaired. A U.S. District Judge ruled on November 28, 2006 that the American bills gave an undue burden to the blind and denied them "meaningful access" to the U.S. currency system. The judge ordered the Treasury Department to begin working on a redesign within 30 days.