 US 12 then heads south to the town of Wallula , intersecting US 730 , then east to Walla Walla , north to Dodge , and east to Clarkston before crossing the Idaho state line over the Snake River just outside Lewiston . US 12 through Walla Walla consists of a four @-@ lane bypass , also known as Inland Empire Highway . The alignment of US 12 through Walla Walla County passes by a number of historical landmarks , such as Whitman Mission and Fort Walla Walla . 
