The most likely name origin is from the Kettle Falls, which early explorers called "La Chaudiére" ("The Boiler"), because of the effervescent water.

A possible alternative is the round holes, shaped like cauldrons, which water had hollowed out in the rocks.

Below Midway, the river loops south, crossing the Canada–US border into the United States, through Ferry County, Washington, before flowing north back into Canada, passing by Grand Forks, British Columbia, where the Granby River joins.

It then flows south, forming part of the Ferry-Stevens County line, before joining the Columbia River near Kettle Falls, Washington.

The Columbia River at this point is a large reservoir impounded behind Grand Coulee Dam, called Lake Roosevelt.