The Mississippi/Missouri river system is the longest in the world. Whoever decided that the north fork (the section originating in Minnesota) was the main channel deprived the Mississippi of "official" longest river status. Two hundred years ago Lewis and Clark headed up the west fork (the Missouri) looking for a water route to the Pacific. A couple of years ago we followed their route across the mountains via a 4WD road at Lolo Pass, and last summer we kayaked into the site of their camp at Fort Clatsop near the mouth of the Columbia River. This year we wanted to kayak another famous section of their route at the "Forks of the Missouri".
The Missouri River originates near the town of Three Forks Montana where the Gallitan, Madison, and Jefferson Rivers come together. We checked into a campground there and started asking questions. We found an outfitter that would provide a shuttle service so we could paddle one of the more scenic stretches of the Jefferson. The section that we wanted to do was 9 miles long and the current was quite strong. So, even though Lewis and Clark traveled upstream, paddling our kayaks downstream seemed like a reasonable concession to us.
I'm constantly amazed with the interesting things we find to do wherever we go!