In this view, looking east, the Clark Fork of the Columbia flows from upper right toward lower center. The Big Blackfoot—so-called to distinguish it from the Little Blackfoot River, which joins the Clark Fork 40 miles upriver from here—flows from upper left to meet the Clark Fork between West Riverside (lower left) and Milltown-Bonner (center). The valley here is dominated by the plywood plant east of the river, which began on that location in 1911, when logs harvested 30 to 50 miles up the Big Blackfoot canyon were floated down to the mill annually on the spring freshet.
The Milltown Dam, built in 1908, identifiable by its frothy spillway at lower center, has become the largest Superfund site in the U.S., owing to the century-long buildup of silt, laden with toxic waste—arsenic, lead and mercury— from copper mines and smelters 180 miles up the Clark Fork.
The Indian road Lewis was following led him through West Riverside, around the toe of the ridge across the river from the plywood plant, and along the narrow north bank of the Big Blackfoot—"Cokahla rishkit, the river of the road to buffaloe." The road up the "East Fork Clark's River" was, Lewis noted on September 9, 1805, "a good rout to the Missouri which the Indians say may be traveled in 4 days." But it led circuitously southeast to the Three Forks (as does Interstate 90 today), whereas Lewis was headed northeast, toward the Falls of the Missouri, where some of his men would prepare for the portage, which would be completed when Sergeant Ordway and his detail arrived from Fortunate Camp with the canoes.
NOTE: On October 17, 2005, the removal was begun of the 30-foot high timber crib dam on the Blackfoot, built in 1886 as a terminus for the annual log drives from upriver (invisible in this photo because submerged by water behind the Milltown Dam). The Milltown Dam was breached in March of 2008, and its removal was complete by the end of that year. The entire reclamation and restoration project was initially scheduled for completion sometime in 2011, but the discovery of a significant amount of submerged but still valuable lumber, among other impediments, delayed the conclusion of the reclamation and restoration until 2014.