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 others being Pasco and Richland). The population was 73,917 at the 2010 census. Book your body rub and nuru massage in Kennewick, WA.