Kennewick is a city in Benton County in the U.S. state of Washington. 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 United States Census Bureau estimated the population to be 84,750 as of 2022, up from 83,921 at the 2020 United States census.