Area code 509 serves eastern Washington, including cities such as Spokane, Yakima, Walla Walla, Pullman, and the Tri-Cities (Kennewick, Pasco, and Richland). Established in 1957 from a split of area code 206, it covers a large and diverse geographic area ranging from farmland to college towns and high desert. The region includes Washington State University and numerous agricultural centers. 509 is critical for connecting rural and urban communities across the eastern half of the state and continues to support growing residential and business needs.