The Stehekin River is a river located in Washington state in the Pacific Northwest of the United States. It is the main river flowing into Lake Chelan. Miners arrived in Stehekin River Valley in the late 19th century. They were followed by homesteaders in the early 20th century. Today, the Stehekin River Valley is still a remote area that can only be reached …The Stehekin River is a river located in Washington state in the Pacific Northwest of the United States. It is the main river flowing into Lake Chelan. Miners arrived in Stehekin River Valley in the late 19th century. They were followed by homesteaders in the early 20th century. Today, the Stehekin River Valley is still a remote area that can only be reached by way of a 55-mile boat ride up Lake Chelan.