Kosmos is an unincorporated community in Washington, United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It was established in 1904 with a grocery store and a post office. Kosmos reached its heyday in the 1940s, when mills and logging camps dotted the landscape. Kosmos was abandoned in 1968 when the Mossyrock Dam

Mossyrock Dam

Mossyrock Dam is a concrete arch-gravity dam on the Cowlitz River near Mossyrock in Lewis County, Washington. The reservoir created by the dam is called Riffe Lake and the primary purpose of the dam is hydroelectric production while flood control is secondary...

 was completed. The Cowlitz River

Cowlitz River

The Cowlitz River is a river in the state of Washington in the United States, a tributary of the Columbia River. Its tributaries drain a large region including the slopes of Mount Rainier, Mount Adams, and Mount St. Helens....

 rose behind the dam, forming Riffe Lake

Riffe Lake

Riffe Lake is a long reservoir on the Cowlitz River in the U.S. state of Washington. Originally named Davisson Lake, it was created in 1968 with the construction of Mossyrock Dam. The lake was renamed in 1976 after the community of Riffe, which was inundated by the lake....

, which completely submerged the town of Kosmos. The remains of the town are periodically exposed when the lake recedes during regional droughts.