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A brief outline of important periods in the history of the confluence of the Big Blackfoot and Clark Fork Rivers.  

Funded by Montana History Foundation and Historic Museum at Fort Missoula.

Illustrations and animations by Joanna Yardley, my design.



Place Names at the Confluence

Surrounded by Woody Mountain, Bonner Mountain, and University Mountain, the river valleys of the Big Blackfoot and Clark Fork Rivers converge, home to the neighborhoods of Bonner, Milltown, Piltzville, and West Riverside.
 B Map-label-edA view of the confluence of the Big Blackfoot and Clark Fork Rivers with placenames.



Glacial Lake Missoula

Glacial Lake Missoula, the largest ice-dammed lake known to have occurred, filled and emptied several times before the end of the last ice age between 15,000 and 13,000 years ago, flooding the region to depths of more than 900 feet.
Glacial Lake Missoula at full pool
This artist's rendition shows Glacial Lake Missoula at full pool with only the tops of Bonner and Woody Mountains showing.



Early History

Native American Use

Time immemorial: Bull trout make spawning runs upriver from Lake Pend d’Oreille through the upper Clark Fork and Blackfoot Rivers to cold clean tributaries.

For thousands of years, the Clark Fork River watershed has been part of the vast aboriginal territories of the Salish and Pend d’Oreille people, who lived as hunters, fishers, and gatherers, moving with the seasons, drawing from a profound knowledge of the plants and animals. In Salish, the confluence of the two rivers is known as Place of Big Bull Trout.
Native American trails have been used since Time Immemorial.The Salish and Pend d’Oreille people and others used well established trails.



Exploration & Occasional Settlement 1806 - 1880

Meriwether Lewis and nine men traveled through the Confluence on July 4, 1806 on their return Voyage of Discovery. Decades later Lt. John Mullan and his crew wintered at Cantonment Wright, located at the Confluence in 1861-2, while building the Mullan military road from Ft. Benton MT to Walla Walla WA. Prospectors used Mullan’s road to get to the gold fields west of Bonner while only the occasional settler remained in the area.
Trails used during periods of exploration.Meriwether Lewis followed a well-established Indian trail. Mullan established a new route.



Transportation Corridors & Capital 1883 - 1964

In the 1880s, the Northern Pacific Railroad provided capital to A. B. Hammond and associates to build a permanent lumber mill supplying the railroad, the copper mines in Butte, and commerce in the Missoula area. The Chicago, Milwaukee, St. Paul & Puget Sound Railroad reached Bonner in 1909. A spur line, the Big Blackfoot Railroad, followed that river to access timber and lumber camps. Hwy 12 followed the Mullan Road through the Clark Fork Valley. Later Route 200 led up the Blackfoot to access Great Falls. In 1964, Interstate 90 passed through Milltown, removing nearly 1/3 of the homes there.
Transportation routes at the ConfluenceSeveral modern transportation routes have been established over the years.



Bonner 1886; others beginning 1890

Bonner was established as a company town to house the managers and superintendents of Hammond’s mill in 1886. Drawn by woods and mill jobs, workers of French-Canadian, Norwegian, Swedish, and Finnish origins soon created the communities of Milltown, West Riverside, Piltzville, and Pine Grove and worked at both Hammond’s (later Anaconda) and William A. Clark’s mills as well as in the logging camps. Japanese railroad workers did not remain. Bonner and area communities were sustained by Anaconda Company’s ownership of the mill until 1972, followed by Champion International and finally Stimson Lumber.
The communities of the ConfluenceBonner, Milltown, West Riverside and Piltzville grew up around the mills.


Milltown Dam

Milltown Dam, 1908

William A. Clark’s hydroelectric dam below the confluence of the Blackfoot and Missoula (now called Clark Fork) rivers produced power for Missoula and Missoula’s street car, the Bonner/Milltown area, the Western Lumber Company, and some areas of the Bitterroot Valley. It was bought by the Montana Power Company after Clark’s death in 1925 and incorporated into the MPC electric grid.
The Milltown DamThe Milltown Dam provided power for the area.



Flood, 1908

The 1908 flood washed tons of sediments laden with heavy metals down the Clark Fork River from Butte and Anaconda and deposited them behind the Milltown Dam. Periodic ice jams scoured the sediments releasing heavy metals including copper, which resulted in fish kills below the dam. In 1981 arsenic was found in the drinking water in Milltown and ultimately Milltown became part of the complex of Superfund sites.
The 1908 flood
Toxic sediments collected behind the Milltown Dam during the 1908 flood.



Present & Future

The 3 R's - Remediation, Restoration, Redevelopment

Remediation at Milltown resulted in the removal of Milltown Dam and some three million tons of contaminated sediment stored behind it. Restoration of the Superfund site returned the Clark Fork River and its floodplain to a naturally functioning condition to be redeveloped and preserved as part of Milltown State Park. The lumber mill at Bonner closed in 2010 and since 2012 the town of Bonner is being revived as new businesses appear. The area communities are no longer dependent on the Bonner Mill for employment.
Aerial view of the Clark Fork restoraton
The story of change at the Confluence continues.



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