They are all “at the top of their game ” now. Any one would be a place to find action. If you are in Island Park, here is a place to consider. Warm River from Warm River Spring downstream can be a pleasure to fish with properly sized equipment. Just above the Upper Mesa Falls access of the Scenic Highway, take the first right which heads east. Follow the well-maintained gravel road to Warm River Spring. Parking areas are abundant near the spring. Take a three or four weight rod and floating line to enjoy rises to PM caddis activity, some PMDs, but mostly fish taking terrestrial insect patterns. Dry attractor patterns work very well. The river below the spring is classic riffle and run water with well vegetated banks. The further you walk downstream, the fewer anglers you will encounter. But anywhere here the number of anglers present will be but a fraction of what you will encounter on the near-by Henry’s Fork. Rainbows, browns, and brookies are what will respond, and they run up to sixteen inches. In the fast water that makes for fun especially with light weight gear.