The Oregon State Quarter was released on June 6, 2005. It features a picture of Crater Lake.
The Montana State Quarter, which features a bison skull, was released on January 29, 2007.
The Washington State Quarter was released on April 2, 2007. It features a picture of a jumping salmon with Mount Rainier in the background.
The Idaho State Quarter features a picture of a Perigrine Falcon and an outline of the state. It was released June 5, 2007.
Alaska's quarter design features a grizzly bear with a salmon in its mouth. The official Alaska state quarter was released into circulation in August 2008.
Check out About.com's "Coins" topic site to find out more about the stories behind each state's quarter.