One of the most popular programs of the U.S. Mint, the 50 State Quarters program was authorized in 1999 and continued through 2008. Earlier coins in the series were often graphically simpler, such as the oak tree featured on the Connecticut quarter (1999) and the Wright Brothers plane for North Carolina (2001); the Kansas quarter (2005) presents a scenographic treatment of a bison and the design for Oregon (2005) condenses an entire landscape onto the surface of the coin. The CFA most recently reviewed coins in this series in June 2018.
(Image credit: United States Mint)