Extension Network Sites > Columbia County > Loading view. There were no results found. There were no results found. Events Columbia County Extension Office Columbia County Extension Office 137 E. Main Dayton, WA 99328 United States Get Directions 509-382-4741 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