Royal Slope is an American Viticultural Area (AVA) located within Adams and Grant Counties in central Washington state. Royal Slope is the state's 15th appellation recognized by the Alcohol and Tobacco Tax and Trade Bureau (TTB), Treasury on October 2, 2020, after reviewing the petition submitted by Alan Busacca, a licensed geologist and founder of Vinitas Vineyard Consultants, LLC, on behalf of the Royal Slope Wine Grower's Association, proposing the viticultural area named “Royal Slope.” The AVA lies between the Quincy Basin and Saddle Mountains surrounding the town of Royal City encompassing 156,389 acres (244 sq mi) entirely within the vast Columbia Valley AVA. There are currently 13 producing commercial vineyards cultivating approximately 14,100 acres (5,706 ha) with only one winery. According to the petition, the distinguishing features of the Royal Slope AVA are its climate, topography, geology, and soils.