The beautiful sub-region of Walla Walla sits within the vast Washington State wine region of Columbia Valley, in the dry and arid, gently sloping lowlands which typify the area. The region has been building up a powerful reputation over the past few decades, and dozens of wineries have opened within the sub-region of Walla Walla over the past twenty years, helping it establish itself as a force to be reckoned with in the world of United States wines. Walla Walla is internationally renowned for the high quality of its Cabernet Sauvignon and Merlot varietal wines, made from imported French grape varietals which adore the dry and arid soils which are found within the region. However, many grape varietals thrive within Walla Walla, and wineries are now expanding their portfolios and creating a wide array of wines. Since it began in the 1820s, wine-production in Washington state has gone from strength to strength, with many of the finest United States wines coming out over the past twenty years hailing from this region. Today, the state is the second largest US producer of wines, behind California, with over forty thousand acres under vine. The state itself is split into two distinct wine regions, separated by the Cascade Range, which casts an important rain shadow over much of the area. As such, the vast majority of vines are grown and cultivated in the dry, arid desert-like area in the eastern half of the state, with the western half producing less than one percent of the state's wines where it is considerably wetter. Washington state is famed for producing many of the most accessible wines of the country, with Merlot and Chardonnay varietal grapes leading the way, and much experimentation with other varietals characterizing the state's produce in the twenty-first century.