Columbia Valley AVA is larger than some states. At 18,000 square miles, or 11 million acres, the appellation covers almost half of Washington State and a small part of Oregon on the south side of the Columbia River. Established in 1984, Columbia Valley contains numerous sub appellations within its boundaries, including Yakima Valley AVA and Walla Walla AVA, both large and important wine districts. Columbia Valley AVA, generally called the Columbia Basin by Pacific Northwesterners, is in the Columbia River Plateau, and the AVA also includes a section of northeastern Oregon. There are dozens of microclimates within this appellation of about 7,000 vineyard acres. Many kinds of grapes are grown in the Columbia Valley, though the principal grapes planted are Cabernet Sauvignon, Merlot, Chardonnay, Riesling, Syrah, Pinot Gris and Sauvignon Blanc. Eastern Washington experiences very hot summers and cold winters, and the northern latitude means that Washington vineyards receive several more hours of sun in the summer than California vineyards. Grapes in Washington therefore have time to develop significant tannins and overall ripeness.