This is the Lochsa River, formed where the Clearwater and Selway meet. I'd camped at that junction, Trois Rivers, in Lowell the night before.
I spent the whole next day climbing Lolo Pass, a 65 mile climb with a 2300 foot elevation gain, so an easy grade. There are no amenities along the way, other than hand pumped well water. Unfortunately, the vandals took the handle. Luckily, there was a van in the Jerry Johnson campground, and people willing to help me out. The rivers here in Idaho and in Montana are deeper, wider (than Colorado), and like this one, clear.
This remains one of my favorite touring days. The ride up Lolo Pass is beautiful, quiet, pristine, and a gentle climb. The road is narrow here, two lanes with no shoulder, but I was fortunate enough to ride while there was construction and traffic was being throttled by the delay. I only saw cars about every 25 minutes, they would all pass me in one steady line, and then I would have the road to myself for another 25 minutes.
That night I camped at the Powell Campground near the Lochsa Lodge, close to the top of Lolo Pass. This made the next day a mighty easy one.