WSU Extension > Yakima County > Loading view. There were no results found. There were no results found. Events Ahtanum Demonstration Garden Ahtanum Demonstration Garden 1000 Ahtanum Blvd Union Gap, Washington 98903 United States Get Directions Today Upcoming Upcoming Select date. Previous Events Today Next Events Subscribe to calendar Google Calendar iCalendar Outlook 365 Outlook Live Export .ics file Export Outlook .ics file