Many consider the 1848 2 1/2 dollar gold piece counterstamped "CAL" to be the first US commemorative coin, as it commemorated the finding of gold in California.
Most standard lists begin with the 1892 half dollar commemorating the 400th anniversary of Columbus discovering America.
Most students of US commemorative coinage acknowledge the break between 1954 and 1982 by classifying those minted from 1892-1954 as Early Commemoratives, and those minted since 1982 as Modern Commemoratives.
Circulating commemorative coins have been somewhat more unusual in the United States.
In 1932, the 200th anniversary of the birth of George Washington, the mint produced a circulating commemorative, the Washington Quarter. In 1934, (no production of quarters in 1933), it became the Regular Issue Coinage design.
In 1975 and 1976, The Washington Quarter was also used to commemorate the United States Bicentennial with a circulating commemorative.
More recently, the Statehood Quarter program began in 1999 with five different circulating commemoratives each year with reverses for each of the states in the United States in the order of their admission into the union.
In 2004-2005 the mint will create a circulating commemorative nickel to commemorate the Louisiana Purchase and the Louis and Clark expedition the Corps of Discovery.
Determining the value of commemorative coins depends largely upon the grade of the coin. See Coin Grading.
External Sites (With pictures)
" class="external">http://www.acoin.com/commem.htm
" class="external">http://www.rich.frb.org/econed/museum/17-18.html
Information on the first commemorative
http://www.coinfacts.com/quarter_eagles/liberty_head_quarter_eagles/1848_cal_quarter_eagle.htm