Chelan County — Thumbnail History (historylink.org) Chelan County embraces the drainages of the Wenatchee River, the Entiat River, and Lake Chelan, and the Chelan River for a total of 2,920 square miles. Irrigation has transformed the arid valleys into agricultural treasure houses and the home to Washington apples and the ubiquitous Aplet and Cotlet confections. Hydroelectric development has lived up to the Wenatchee Daily World’s claim, first made in the 1920s, that the region is the “Power Belt of the Great Northwest.” Almost 90 percent of the county is owned by the state and federal governments.