Watershed Facts

The Clark Fork watershed at a glance:

  • sutton flyfishing blackfootForms the northern headwaters of the Columbia River system in Montana and Idaho
  • Covers 14 million acres
  • Includes 28,000 miles of rivers and streams
  • Supports 350,000 people
  • Largest river in Montana by volume
  • Sustains agricultural operations with irrigation water
  • Boasts spectacular recreation on world-class lakes and creeks
  • Provides community drinking water from ground and surface water sources
  • Begins near Butte where Silver Bow and Warm Springs creeks come together
  • Ends when it joins stunning Lake Pend Oreille near Sandpoint


butte miningFor centuries, the watershed provided fish for Native American tribes. The confluence of the Clark Fork and Blackfoot rivers near Missoula was called the “place of the big bull trout” by local tribes.

In the course of their historic journey to the Pacific Ocean, Lewis and Clark explored much of the Clark Fork Basin. In fact, the Clark Fork was ultimately named for William Clark himself.

The Montana gold rush of the 1860s brought with it an influx of settlers, along with the railroad. Butte, Montana was the largest city in the West by 1900, thanks to the mining boom.

Unfortunately, decades of heavy use on this hard-working river took a toll. Mining pollution, along with logging, smelting, agricultural production, and development have left their mark on our watershed. The Upper Clark Fork is the largest Superfund complex in the United States.

The Clark Fork today

Family smiling on lake-low resThe Clark Fork River is on the mend, and part of the biggest restoration story of our time. Thanks to the removal of Milltown Dam and the remarkable recovery of Silver Bow Creek, fish are returning to headwaters, water is cleaner, and communities more vibrant.

Now, the Superfund cleanup along the Upper Clark Fork River is underway, a decades-long, 56-mile, collaborative effort to remove pollution from working ranchlands and the river’s floodplain.

Across the basin, communities are embracing the value of clean water and healthy rivers. Learn more about our work to protect and restore this remarkable watershed, and become a member to be a part of the story.