* Two new nickels were introduced in 2004. Jefferson remained on the obverse; the reverse featured images of the Louisiana Purchase and the Lewis and Clark expedition.

** 1975–1976 Bicentennial reverses were minted. These coins are dated 1776–1976; none were individually dated 1975 or 1976. The double date of 1776–1976, with a temporary Bicentennial reverse, was carried on the Quarter (Colonial Drummer), Half Dollar (Independence Hall), and Eisenhower Dollar (Liberty Bell/Moon). The Eisenhower Dollar (1971–1978) carried the Bicentennial Reverse in 1975 and 1976.

*** The U.S. government introduced the 50 State Quarters Program Act in 1999. It features new quarters with unique state designs on the back. Five coins have debuted each year since 1999, and five new quarters will be released every year until 2008. The quarters are being released in the order that the states joined the union.