Because priviate property impedes drivers from following the military road into current Columbia County , drivers stay in Walla Walla County until just before crossing the Lyons Ferry Bridge , where the Palouse River flows south into the Snake River , and crosses Columbia County in its northwest corner . Crossing the Snake River at the Josso High Bridge on SR 261 and passing by the Lyons Ferry Park , Franklin County , a short side trip to Palouse Falls State Park is available by turning right at Palouse Falls Road . In 1839 , when the missionaries Walker , Eells , and their families traveled from the Whitman Mission at Waiilatpu to Tshimakain Mission , they detoured to visit these falls . Paul Kane , artist came a decade later , and became the first to draw an image of the falls on July 14 and 15 , 1847 . Continuing on SR 261 and turning north at Nunamaker Road , the route eventually reconnects with SR 261 , where it becomes SR 260 , and proceeds towards Washtucna , Adams County
Whitman Mission
Whitman massacre
Fort Walla Walla–Fort Colville Military Road