The area code 509 is located in Kennewick, Washington.
Area code 509 serves Kennewick, Washington, and most of eastern Washington. Centered in the Tri-Cities along the Columbia River, Kennewick sits near the meeting of the Columbia, Snake, and Yakima rivers, making it a key hub for travel, energy, and agriculture. The 509 area code spans the Columbia Basin and the Palouse, connecting small farm towns with larger cities, research centers, and outdoor destinations. All 509 phone numbers follow the Pacific Time zone.
Established: 1957 (North American Numbering Plan Administrator)
Major cities and communities covered by area code 509 include:
In and around Kennewick, landmarks include the Columbia River waterfront and the nearby Hanford Reach National Monument. Across the 509 region, you’ll also find Grand Coulee Dam and Lake Roosevelt National Recreation Area.
History and dialing: Area code 509 was created in 1957 when Washington’s original 206 was split, assigning 509 to eastern Washington. It remains the single area code for this side of the state, including Kennewick and the Tri-Cities. Washington uses 10‑digit dialing for all calls, so you’ll dial the area code plus the phone number for local and long‑distance calls within 509. Local number portability lets you keep a 509 phone number when switching carriers or moving within the region.