The Railroad Ranch section of the Henrys Fork of the Snake River-so named because this land was once owned by the Harriman family of Union Pacific Railroad fame and subsequently gifted to Idaho as a state park in 1977-is now the Harvard of the flyfishing world. Here, after the narrow Box Canyon section of the Henrys Fork opens into wide, exposed, and subtle current breaks, wild trout sip in clear churning channels at an intricate profusion of insect life. If your timing is right, such as during the famed brown drake hatch, the rewards can be staggering. But bring a subpar game to the Henrys Fork during the dog days of August and you’ll inevitably get humbled. Five perfect presentations with the wrong fly will reap the same results as five so-so presentations with a spot-on pattern: zip. Know how to cast in the wind, and match the hatch to a tee, or you’ll be scratching your head. That’s why many of the hardest of the hardcore call this river home. More info: Mike Lawson’s Henry’s Fork Anglers, 800-788-4479; TroutHunter, 208-558-9900;

Next Best: Silver Creek, Picabo, Idaho Don’t play around in these S-curves when the Callibaetis are hatching unless you know how to handle long leaders and light tippet. More info: Silver Creek Outfitters, 800-732-5687;