Clark Fork, Idaho — Montana's River Arrives at an Idaho Lake

Clark Fork sits where the river of the same name enters Lake Pend Oreille after traveling hundreds of miles across western Montana.

By the time it reaches Idaho, the Clark Fork drains an enormous mountain watershed.

The town developed where river, railroad and mountains squeeze transportation into the same corridor. The Northern Pacific followed that route through the nineteenth-century West, and timber and mining added traffic.

The river also carried the environmental legacy of mining districts far upstream in Montana, linking cleanup hundreds of miles away with water eventually entering Idaho.

Lake Pend Oreille receives most of its inflow from the Clark Fork.

That makes this small town the site of a hydrological handoff on a continental scale: Montana supplies the river; Idaho receives it as a lake.