Prosser is the county seat of Benton County, Washington. Prosser has more than 30 wineries in an area of about ten-by-ten miles.
Prosser is located in the heart of Washington Wine Country. Since 1919 Prosser has been the home of the Washington State University Irrigated Agricultural Research Extension Center (WSU-IAREC). Dr. Walter Clore researched and tested more than 250 American, European, and hybrid grape varietals. His research proved that vinifera grapes could be grown successfully in the area and would produce fine wine. Thus was born the Washington wine industry.