I am not afraid to admit my interest in tailwater streams and large rainbow and brown trout, but cutthroat trout, especially the west-slope cutthroat, are a rare breed and I give them full respect, especially when chasing that beautiful fish in its north-central Idaho bastion.
It’s there, in an area stretching from Coeur D’Alene southeast to Salmon, that tumbling mountain streams, such as the St. Joe, Coeur D’ Alene, Lochsa, Selway and Kelly Creek, drain off the west slopes of the Bitterroot Mountains, which divide that portion of the Gem State from Montana. Those streams carve between steep, pine-tree laden slopes ripe with mule deer, elk, mountain grouse, mountain lions and black bear. I’m not aware of another place in the world (maybe southern British Columbia, maybe) where so many quality native west-slope cutthroat streams can be found in such a confined area. It’s wild, remote country, mostly located away from paved highways, where anglers may discover that sometimes a cutthroat isn’t just any cutthroat–-in this steep portion of Idaho sometimes a cutthroat stretches 20 inches or more, a trout I’d take on any stream in the West. Fortunately, if you can make it to one or more of these streams in the next month and a half you’re going to nail it just right—fall color is infiltrating the cottonwoods and aspen and October caddis and Baetis mayflies are starting to show. When that happens, 30, even 40 fish days are possible. 
If you were to visit Kelly Creek tomorrow you would find excellent fishing for native west-slope cutthroat that commonly stretch between 10 and 17 inches. A few fish exceeding that size are possible, but should not be expected. However, dedicated anglers occasionally walk away from the stream having landed and released a fish in the 18-to 20-inch range. Let me put it this way: people who fish the stream regularly won’t call you a liar when you describe a three or four-pound cutthroat from Kelly Creek. However, anglers who are truly bent on catching a big cutthroat (I won’t blame you if you fall into that category), must bring a game plan to Kelly Creek because the river’s largest trout are highly migratory. During winter those fish are found downstream from Kelly Creek in the North Fork Clearwater, especially in the slow-moving backwaters of Dworshak Reservoir. During spring and early summer they ascend the North Fork and move into Kelly Creek. In June and July some large fish can be found in the mainstem sections of Kelly, but many mature fish are up in the tributaries spawning. The tributaries of Kelly Creek do not open until July 1. After spawning, some big cutts move back into Kelly Creek and remain there until the hot weather really hits in late July and August. During very dry, hot years most of the large fish move back into the tributaries, such as Cayuse Creek and Bear Creek, where they find cool water. By early-September the big cutts drift out of the tributaries and into the main river. They’ll linger for a few days or even a few weeks then head downstream into the North Fork. By early October, Kelly Creek hosts mostly small trout in the six to 12-inch range. In effect, Kelly Creek and the North Fork Clearwater are one stream and should be considered as such by those anglers specifically shooting for a large west-slope cutthroat.
For a mid-sized mountain freestone stream, Kelly Creek is quite fertile and produces quality hatches all season, beginning with the big stoneflies in late May and June. The river’s cutthroat drill large stoneflies at that time, both golden stones and the larger Pteronarcys (also called salmonflies), but high water severely restricts angler access to the stream. In fact, Kelly Creek can offer nearly impossible conditions from its late May opener through the Fourth of July holiday. Typically, anglers find the river dropping into shape by the mid-summer holiday if not a week to 10 days prior to that event during dry years. Caddisflies also are present early in the season and they remain on the water through summer, extending into fall with the emergence of the giant fall caddis (don’t worry, we’ll cover the intricacies of fall caddis later). Pale morning duns are found on the water through June and July and anglers may even find green drakes on the water prior to mid-July. Terrestrials are important food items for Kelly Creek’s cutthroat between late July and mid-September. Grasshopper, ant and beetle imitations should be carried in your fly boxes. During fall, meaning right now, those aforementioned Baetis mayflies and the fall caddis provide killer fishing opportunities. You could see some competition on Kelly Creek, especially if you fish the weekends. If that’s the case, don’t fret, just put on your hiking boots and head out because Kelly Creek offers great hike-in fishing. The hike-in option begins about 10 miles above Kelly Creek’s confluence with the North Fork at a bridge crossing adjacent to Kelly Creek Campground. A narrow trailhead starts along the north bank and follows the creek east for 20 miles. Footpower and horsepower are the only ways in, so once you’ve covered a few miles you’ll find untouched water and fish that aren’t as discerning as their downstream friends. Hiking in to upper Kelly Creek and Cayuse Creek ranks as one of the West’s most enjoyable fly-fishing trips. One time I set up camp in a meadow and fished steadily until near dark landing more cutthroats than required to feel completely content. I wandered back to the camp, met friends and cooked dinner on a tiny pack stove. We sat around a modest campfire late into the evening brewing coffee, adding various liquids, feeling the good burn. We swapped jokes you wouldn’t tell in your mother’s presence and buckled over at the waist laughing until someone said, “Please, stop! I can’t breath,” or “Ouch, man! Stomach cramp! Stomach cramp!” We retired to the tents before things got out of hand, then woke in the a.m. and fished hard all day casting dries and nymphs into the most emerald pools you could imagine. I remember feeling a long, long way from the disturbances of our modern world and I didn’t ever want to leave. A kid born again. That’s what camping and fishing for Kelly Creek’s cutthroats can do.
For the next eight weeks or so, the creek’s Baetis emergence should begin around 10:30 a.m. and it extends through the afternoon. At that time, you’ll find pods of fish feeding off the surface and they can be taken on a variety of patterns, including parachute Adams’, olive sparkle duns, and cripples. Underneath, those trout pound hare’s-ears, pheasant-tails, RS-2 emergers, CDC Baetis emergers and brassies. Also during fall, flyfishers encounter that big fall caddis and this is no sparse emergence. Never have I seen so many fall caddis in the air or on the water or landing on my body as when fishing Kelly Creek in October. It’s a serious hatch, not just a few insects here or there. The trout know they are there and drill many caddis patterns, on the surface and underneath it. Size-8 Cinnamon stimulators, bucktail caddis, and the elk-hair October caddis are prime choices. Underneath, those cutthroats seam partial to size-6 and size-8 beadhead October caddis larvae and orange or pale serendipities.
During a couple fall visits to Kelly Creek I’ve landed as many as 30 cutthroat on parachute Adams’ and elk-hair October caddis in a single afternoon and had just as many refuse my offerings. On one of those occasions, a friend, Dan Summerfield, rose 19 fish on successive casts and missed 14 of them. He was throwing a size-22 Trico imitation during a Baetis hatch (I didn’t ask why because you couldn’t argue with the result). He ended his Trico affair when a big fish straightened the paltry hook. On that day there were elk bugling in the mountains, the cottonwoods and aspens were lit in gold and yellow, the river was mostly deserted, and I harbored four ruffed grouse in the cooler ready to be seasoned and baked in foil for dinner. There was enough liquid refreshment left for another evening camped next to Kelly Creek and the North Fork Clearwater and I wasn’t required to be anywhere in particular for a month. It was all good, as it usually is on Kelly Creek, one of the West’s greatest native west-slope cutthroat streams.