Big Horn River Fly Fishing Near Thermopolis
Private Trip
River Fishing
Tailwater fishery features browns, rainbows, and cutthroat trout averaging 16-18 inchesCalmer waters provide excellent dry fly fishing opportunities near ThermopolisIntimate 2-guest capacity ensures personalized instruction and skill development
When folks ask me about the best tailwater fishing in Wyoming, the Big Horn River always tops my list. This gem flows right through Thermopolis, about 80 miles south of Cody, and it's become a customer favorite for good reason. Unlike the rowdy freestone rivers that'll have you white-knuckling your rod, the Big Horn runs smooth and steady – perfect for honing your technique or finally landing that trophy trout you've been chasing. With browns, rainbows, and cutthroat averaging 16-18 inches and plenty pushing into the 20+ range, this world-class fishery delivers consistent action that'll keep you casting from dawn to dusk.
The Big Horn's tailwater nature means cold, nutrient-rich water year-round, creating a bug factory that keeps these trout fat and happy. You'll be floating a calmer stretch than most Wyoming rivers, which gives you time to really work your presentations and study the water. The gradient here is gentle, with long pools, meandering channels, and plenty of structure where trout love to hold. We'll launch right in Thermopolis and work our way downstream, hitting the prime lies where I've been putting clients on fish for years. The river runs clear most of the season, so sight fishing becomes a real possibility – there's nothing like watching a 20-inch brown slowly rise to inspect your dry fly before committing. With just two anglers per trip, you'll get personalized instruction and plenty of water to cover without feeling rushed.
This top-rated tailwater responds beautifully to dry fly fishing, especially during the warmer months when hatches come off regularly. We're talking PMDs, BWOs, caddis, and terrestrials that'll have trout looking up from June through September. I'll rig you up with a classic dry-dropper setup – a visible dry on top with a nymph trailing below – so you're covering the entire water column. When the surface action slows, we'll switch to indicator nymphing with patterns that match the abundant aquatic insects. The river's consistent flows mean your drift doesn't need to be perfect every time, giving newer anglers a chance to dial in their technique without the pressure of fast pocket water. Experienced fly fishers love the technical aspects here – these fish see plenty of flies, so your presentation needs to be on point. I keep a selection of local patterns that have proven themselves over years of guiding this water, from size 18 Baetis nymphs to foam hoppers that'll pull browns out of the deepest undercuts.
Brown trout rule the roost in the Big Horn, and these aren't your typical skinny mountain fish. Fed by consistent bug life and steady water temperatures, browns here grow thick and strong, with most falling between 14-20 inches and the occasional bruiser pushing 24+. They're most active during spring and fall, becoming opportunistic feeders that'll smash streamers along the banks or sip tiny mayflies in the film. What makes browns special here is their wariness – they've seen every fly pattern imaginable, so when you finally fool one, it feels earned. They fight like bulldogs in this system, using the current and structure to their advantage.
Rainbow trout in the Big Horn are absolute rockets, averaging 15-18 inches with chrome-bright sides that'll blind you in the Wyoming sun. Unlike browns that hug cover, rainbows cruise the main channels and aren't afraid to chase down a well-presented fly. Peak rainbow action happens from April through June when they're most aggressive, though they'll feed consistently through summer if you hit the right water at the right time. These fish jump like tarpon when hooked – I've seen 16-inch rainbows clear the water three times in a single fight. Their willingness to take dry flies makes them perfect targets for anglers wanting that visual take experience.
Cutthroat trout add that native Wyoming flavor to your day on the water. While less common than browns and rainbows, the cuts here are stunning fish with those distinctive red slashes and spotted flanks. They typically run 12-16 inches but make up for size with attitude – cuts will often take flies that spookier trout refuse. They're most active during summer months and absolutely love terrestrial patterns like hoppers and ants. Finding cutthroat feels like discovering hidden treasure, especially when you're targeting them in the quieter side channels where they like to hold. They're also the most photogenic fish in the system, with colors that pop against the Big Horn's blue-green water.
The Big Horn River delivers world-class fishing in a setting that lets you actually enjoy the experience without fighting the current every cast. Whether you're looking to improve your dry fly technique, land your first 20-inch trout, or simply spend a day on renowned Wyoming water, this trip checks all the boxes. With lunch included and water that fishes well from spring through fall, you'll get maximum time on the water with minimal hassle. The combination of consistent action, beautiful scenery, and the chance at a true trophy makes this a trending choice among serious anglers. Don't wait – prime dates on the Big Horn fill up fast, especially during peak season when the dry fly fishing really turns on.
The Clackacraft 16WF is the gold standard for drift boats on waters like the Big Horn River. Built with a bulletproof hull that can handle rocky shallows and snags, this boat features an interior moved forward six inches for perfect balance when working the productive runs and pools. With room for two anglers, you'll have plenty of space to cast while your guide navigates the calmer flows that make the Big Horn ideal for dry fly fishing. The stable platform lets you focus on presenting flies to those chunky 16-18" browns and rainbows without worrying about boat movement. Whether you're working on your technique or chasing that trophy cutthroat, this proven design gives you the best shot at success on one of Wyoming's premier tailwater fisheries flowing right through Thermopolis.
Tylosurus AcusBrowns are the smart guys of the Big Horn - they've seen every fly in the book and earned their reputation as tough customers. Most run 16-20 inches here, with some bigger ones lurking in the deeper pools and undercut banks. They're most active during low light conditions, making early morning and evening prime time. Fall is when they really turn on, feeding heavily before winter. What guests love about browns is the challenge - they fight dirty with powerful runs and head shakes that'll test your drag. The meat is top-notch too, with a rich flavor. Pro tip: when nothing else works, try dead-drifting a small pheasant tail nymph tight to the bank structure where they hide.
Oncorhynchus ClarkiiCutthroats are easy to spot with that signature red slash under their jaw - that's where the name comes from. On the Big Horn, they typically run 14-20 inches and love hanging around structure like fallen logs and undercut banks. These native Wyoming fish are most active during morning and evening hours, especially in spring and fall when water temps are perfect. What makes them special is they're less spooky than browns but still put up a solid fight with some nice head shakes. They're also excellent eating with sweet, firm meat. Here's a local tip: when the mayflies are hatching, drift a small elk hair caddis along the bank edges where the current slows - cutthroats can't resist it.
Oncorhynchus MykissRainbows are the acrobats of the Big Horn, known for their flashy jumps and that beautiful pink stripe running down their sides. They average 15-18 inches here and prefer the faster water with good oxygen flow - look for them in riffles and current breaks. Spring through early summer is prime time when they're most aggressive, especially during insect hatches. Guests love rainbows because they fight hard and aerial, plus they're forgiving for newer fly fishers. The pink meat is mild and tasty too. Local secret: during PMD hatches in late spring, use a size 16 parachute Adams fished right in the foam lines where the fast water meets slower pools - they hammer it.
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