The famed Meriwether Lewis & William Clark expedition occurred during the presidency of Thomas Jefferson. Therefore, it was deemed appropriate to celebrate the 200th anniversay of the expedition by creating special designs for the Jefferson Nickel. Four designs were created, as follows:
2004 Peace Medal - obverse using the traditional Thomas Jefferson design from 1938-2003; reverse featuring crossed peace pipe and tomahawk above clasped hands (copying the design seen on most of the Indian Peace medals issued by the U.S. government).
2004 Keel Boat - same obverse as preceding; reverse featuring the boat used by Lewis and Clark to navigate waterways in the beginning of their expedition.
2005 American Bison - new obverse showing an off-center profile of Jefferson facing right; reverse with an American bison reminiscent of the design on the "Buffalo" Nickel (1913-1938).
2005 Western Waters - same obverse as preceding; reverse with a view of the Pacific Ocean and the inscription "Ocean in view! Oh the joy! (from an entry in Clark's journal).