SR 21 originates at an intersection with , about east of the northern terminus of ;[REF] both intersections are in the city of Kahlotus, which is located in a narrow valley near several coulees in Franklin County.
The ferry travels across the Lincoln County line to enter Ferry County, named after Elisha P. Ferry, the first Washington governor,[REF] southwest of Keller in the Colville Indian Reservation [REF].