The U.S. $1 bill is the most common amount of United States money. It became a Federal Reserve Note in 1963. The design of the bill is the second oldest of U.S. currency currently being printed, coming short only to the United States $2 bill. The front of the bill has a painting by Gilbert Stuart of George Washington, the first U.S. president, and the reverse has a picture of the Great Seal of the United States. About 45% of all U.S. money made today are $1 bills and according to the Bureau of Engraving and Printing, the life span of a $1 bill in circulation is 21 months before it is too worn out and is replaced.

There have been two sizes of U.S. $1 bills: the large size notes and the current small size notes. The first $1 bill was issued in 1862 as a Legal Tender Note. From that time on, the $1 bill had variety of designs including the popular silver certificate, which was first issued in 1886 with Martha Washington, the first woman on U.S. currency on the front of it. The small size notes were first introduced in 1929 and it was issued as a silver certificate under the Series of 1928. Around World War II, in 1942, special issues of one-dollar bills were started. These included special $1 Silver Certificates for Hawaii in case of Japanese invasion which had Hawaii printed vertically on the left and right side with a brown seal and serial number. Another special $1 Silver Certificate for the payment of Allied troops in North Africa about to start an assault in Europe, which had a yellow seal. These two special Silver Certificates could be claimed as worthless enemy troops got a hold of them. One-dollar Federal Reserve Notes started being printed in 1963, therefore ending the production of the Silver Certificate.