Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Skamania County is a county located in the U.S. state of Washington. Its name derives from the Chinookan word for swift water, a reference to the Columbia River. As of 2000[update], the population was 9,872. The county seat is at Stevenson, which is also the county''s largest city, although the Carson River Valley CDP is more populous. Skamania County was formed on March 9, 1854.