Kennewick is a city in Benton County, Washington, United States. It is located along the southwest bank of the Columbia River, just southeast of the confluence of the Columbia and Yakima rivers and across from the confluence of the Columbia and Snake rivers. It is the most populous of the three cities collectively referred to as the Tri-Cities. The population was 83,921 at the 2020 census, and was estimated at 86,728 in 2024.