The Clark Fork River runs for 327.4 miles through six Montana counties – Sanders, Mineral, Missoula, Powell, Granite, and Deer Lodge.

The Clark Fork River has its headwaters in the Silver Bow (or Highland) Mountains, originating at the confluence of Silver Bow and Warm Springs creeks near Anaconda, Montana. The river flows north and west 350 miles through broad, semi-arid valleys, high mountain ranges, and steep-sided valleys and terminates in Lake Pend Oreille, Idaho.

When the Clark Fork crosses the Idaho border, it is Montana’s largest river, carrying an average 22,060 cubic feet of water per second.