<P> North American area code 509 is the telephone area code for the eastern two - thirds of Washington . The western boundary of 509 roughly follows the Cascades . The 509 area includes Spokane, the Tri-Cities (Richland, Pasco, and Kennewick), Ellensburg, Yakima, Walla Walla, and Wenatchee . The 509 code was created in a split from 206, originally the area code for all of Washington, in a flash - cut on January 1, 1957 . </P> <P> This part of Washington is not as densely populated as the west, and the great majority of the state's landlines and cell phones are located west of the Cascades . As a result, while western Washington went from one area code to four during the 1990s, 509 has remained unchanged for over 60 years . With western Washington being overlaid with area code 564 in 2017, 509 is the only portion of Washington where seven - digit local dialing is still possible . </P>

Where is area code 509 located in usa