2020 Map of Lower Monumental Dam

About this map

The Snake River carves a deep path through the plateau in this part of Franklin and Walla Walla Counties, anchored by the massive Lower Monumental Dam. The resulting reservoirs, Lake Herbert G West and Lake Sacajawea, have transformed the landscape, inundating previous riverine geography and creating a distinct industrial and recreational corridor. Along the banks, the Columbia Plateau State Park Trail follows the river's winding course, tracing a route through a series of dramatic coulees and canyons such as Dunnigan Coulee and Devils Canyon. Small settlements and landing points like Windust, Farrington, and Scott are scattered along the water's edge. This terrain is further marked by transportation infrastructure essential to the region, including the Lower Monumental State Airport and the Hille Airstrip, which serve this remote stretch of the Pacific Northwest.