Lake Wallula is a reservoir on the Columbia River in the United States, between the U.S. states of Washington and Oregon. It was created in 1954 with the construction of McNary Dam. It reaches from McNary Dam near the city of Umatilla, Oregon, to the Tri-Cities of Washington. Lake Wallula is part of the vast Columbia Basin, a region renowned for its agricultural productivity, hydroelectric power generation, and a destination for recreational activities.