2017 Map of Lower Monumental Dam

About this map

The Snake River carves a deep path through the basalt plateau at the border of Franklin and Walla Walla Counties, anchored by the massive infrastructure of the Lower Monumental Dam. This 2017 survey illustrates a landscape defined by the impounded waters of Lake Sacajawea and Lake Herbert G W, which have transformed the river's original character. Small settlements and transit points like Windust, Farrington, and Matthew are scattered along the steep-walled corridor, connected by roads such as Devils Canyon Rd and Pasco Kahlotus Road. The terrain is marked by dramatic geological formations, including Devils Canyon, Dunnigan Coulee, and Box Canyon, showing the erosional power of the region's drainage patterns. Aviation access is noted through the Lower Monumental State Airport and the remote Hille Airstrip, serving this sparsely populated but infrastructure-critical section of eastern Washington.