 It encompasses the valleys formed by the Columbia River and its tributaries, including the Walla Walla River, the Snake River, and the Yakima River.The Columbia valley stretches between the 46th parallel and 47th parallel which puts it in line with the well known French wine growing regions of Bordeaux and Burgundy.The northern latitude gives the areas two more hours of additional daylight during the summer growing season than wine regions of California receive.