

As of April 1, 2021, the Washington State Office of Financial Management, Forecasting Division estimates the cities as having a combined population of 224,640. The combined population of the three principal cities themselves was 220,959 at the 2020 census. MSA estimates show the Tri-Cities population as over 300,000.

The official 2016 estimate of the Tri-Cities MSA population is 283,869, a more than 12% increase from 2010. The Tri-Cities urban area consists of the city of West Richland, the census-designated places (CDP) of West Pasco and Finley, as well as the CDP of Burbank, despite the latter being located in Walla Walla County. The three cities function as the center of the Tri-Cities metropolitan area, which consists of Benton and Franklin counties. The cities border one another, making the Tri-Cities seem like one uninterrupted mid-sized city. The Tri-Cities are three closely linked cities ( Kennewick, Pasco, and Richland) at the confluence of the Yakima, Snake, and Columbia Rivers in the Columbia Basin of Eastern Washington.
