P: Palouse River:
The Palouse River snakes its way through Whitman County, Washington, and Latah County, Idaho. The South Fork runs through Pullman, Albion, and Colfax, where it combines with the North Fork, which has wound through Palouse and Elberton.
The combined river then runs near Winona, and is the river of Palouse Falls (below). Eventually it flows into the Snake River, which flows into the mighty Columbia River, and then out into the Pacific Ocean.
Watch a video of Tyler Brandt kayaking over Palouse Falls, an almost 190' drop. It's scary and amazing.
Newspaper article about the stunt.
The top picture was taken from our River Ranch, several miles after the two forks combine in Colfax.