The Wahluke Slope appellation was authorized as an official Washington State appellation in 2006.  North of the Yakima Valley, it is one of the state's warmest growing regions, and 8,491 acres to date (April, 2017) out of the AVA's 81,000 acre total are planted to a variety of wine grapes, producing about 20 percent of the entire Washington State harvest each year.

       The Columbia River drifts lazily through the gap in the Saddle Mountains and curves to form Wahluke Slope's southern and western boundaries.  It is the only appellation in the Pacific Northwest that is a single geological landform.  The region is a giant alluvial fan created by repetitive flooding events.

        Of the four newest Washington appellations within the Columbia Valley AVA, the Wahluke Slop may hold the most untapped potential.  An 81,000-acre triangular slice of desolate scrubland, it is nestled above the Columbia River in south-central Washington and wins high marks for the way its concentrated heat ripens Merlot and Cabernet Franc.

         Much of the appellation was created by The Great Missoula Floods that exploded through ice dams thousands of years ago, ripping land and rocks from their paths during the final stages of the last ice age.  Unimaginable volumes of floodwaters propelled icebergs and boulders across the Columbia Basin.  Locally, floods burst through Sentinel Gap near Mattawa on the Wahluke Slope, grinding basaltic lava flows into tiny particles and dumping boulders, some the size of houses, across the area.  Layers of silt and wind-blown sand form the surface through which grapevines send their roots.  Gravelly, rocky soil, combined with a dry, warm climate, make Wahluke Slope one of the best places in Washington to grow wine grapes.

• Wahluke Slope AVA (2006)  81,000 acres; 5,200 in production (at AVA authorization); two wineries; three custom crush facilities. Grant County, eastern Washington.  Totally within the macro appellation of the Columbia Valley.  Twenty vineyards.  One of Washington's warmest regions.  Elevation ranges from 425 feet along the Columbia River to 1,475 feet atop the highest irrigated lands.
   
• Noted for its grapes, mostly Merlot, Syrah, Cabernet Sauvignon, Riesling, Chardonnay and Chenin Blanc; not yet for its wineries.
   
• Wineries:  Two wineries currently operate in the Wahluke Slope AVA - Fox Estate Winery and Ginkgo Forest Winery.  Jerry Fox and his family have been growing wine grapes on their Fox Estate Vineyard since the early 1980s. Ginkgo Forest Winery opened its tasting room in 2007; a second tasting room in Tacoma was opened in July of 2013.  Also operating on the Slope are three crush facilities.  The Millbrandt Family's Wahluke Wine Company located near Mattawa is a custom-crush facility where bulk wine is made for growers and other wineries; it is not open to the public, but the Millbrandt's opened their own winery and tasting room in Prosser.  Coventry Vale, another customer crush facility, operates a production facility in the far eastern part of the Slope.  It, too, is not open to the public, nor is the crush facility of Lost River Winery also operating on Wahluke Slope; Lost River's barrel cellar and tasting room is located in Winthrop, Washington, to the north.
   
• Wines made with Wahluke Slope grapes:  Grapes grown in this region are used by wineries throughout the Northwest... far too many to mention.  This partial list will give you at least an idea of the credibility of the region and the quality of its grapes:  Bergevin Lane, Chateau Ste Michelle, Chatter Creek, Columbia Crest,  Desert Wind, Duck Pond Cellars (Oregon), Hogue Cellars, Isenhower Cellars, K Cellars, Latah Creek, Lost River Winery, Northstar, Snoqualmie Vineyards,  St. Laurent Winery , Syncline Wine Cellars, Three Rivers Winery, and many, many more. Mourvčdre, Primitivo, Malbec, and Petit Verdot, relatively new varietals to Pacific Northwest wine regions, are all planted on Wahluke Slope.
   
• Some Wahluke Slope vineyards: 
   
  • Milbrandt Vineyards
  • Lucky Bohemian Farms - 260 acres planted to Merlot, Syrah, Cabernet Sauvignon and other heat-loving varietals;
  • Indian Wells Vineyard - flagship vineyard for Chateau Ste Michelle;
  • Rosebud Vineyard planted by members of the Dodson family in 1978;
  • Fox Estate Vineyard - planted by the Fox family in the early 80s;
  • Stone Tree Vineyard - 450-acre vineyard planted to clones of Grenache,
  • Clifton Vineyard - 500-acre vineyard owned by the Millbrandt family;
  • Desert Wind Vineyard - 540-acre estate vineyard owned by the same family as owns Duck Pond Cellars in Oregon;
  • Winebau Vineyard - Sagemoor Farms owns this vineyard;
  • Wahluke Slope Vineyard;
  • Dick Shaw vineyards;
  • Jack Jones vineyards
     
• Top Grape Varietals:  Merlot, Syrah, Cabernet Sauvignon, Riesling, Chardonnay, and Chenin Blanc.