There is a very famous volcano in the state of Washington, it is called Mount Rainier!It is 14,410 (4,392-m) tall. This volcano is dormant. The last time it erupted was about 2,000 years ago. Even though there is alot of interesting facts about Mount Rainier I will give you three. It is the tallest volcano in Washington. the slopes support one of the largest glacial systems in the United States. George Vancouver saw the mountain in 1792 and named it for fellow navigator Peter Rainier.