Bighorn River cheat sheet
Both trout, what's hatching by month, the licence and the rules, the three fly rigs and the one outfit. One page to take to the water.
Bighorn River
The tailwater fishes all year. Mid-June to early September is peak dry fly; autumn for big browns on streamers; winter is midges. Match the hatch on your dates.
Licence
A Montana fishing licence from Montana FWP, in three parts: conservation licence ($10), AIS prevention pass ($7.50) and a fishing licence by duration. 2026 non-resident totals: 1-day $31.50, 5-day $73.50, season $117.50 (as of 5 June 2026). Buy online at fwp.mt.gov or the MyFWP app (no more over-the-counter sales). A state licence is required even on the Crow Reservation stretch.
The rules
Artificial lures only on the main stretch (the cable below the Afterbay down to the Bighorn Access), no bait. Standard trout limit (5 daily, only 1 over 18 in). Release is the norm. Pinch your barbs and clean your kit between rivers.
Release / handle with care
Almost everyone returns Bighorn trout. Pinch the barb, use a rubber-mesh net, keep the fish in the water, wet your hands, and face it into the current to recover. Clean, Drain, Dry between waters for the AIS rules.
Bank vs boat · season · time → rig
| Fish | The water | Season / time | Rig |
|---|---|---|---|
| Rainbow and brown (search) | Riffles and runs, all over | All year, the default | Nymph rig (indicator, scud/sowbug + dropper) |
| Rainbow and brown (rising) | Smooth runs and slicks, during a hatch | Hatch windows: baetis (spring/autumn), PMD and trico (summer), midge (winter) | Dry fly rig |
| Brown (the bigger fish) | Banks, undercuts, seams | Autumn and spring, low light | Streamer rig |
| Searching when nothing is rising | Anywhere | Most of the day, most months | Nymph rig (the workhorse) |
Not sure? Fish the nymph rig. Change to the dry fly when you see noses in the slicks; tie on a streamer for a big brown on a grey autumn day.
The rigs
Floating line → tapered leader → tippet → scud/sowbug and a smaller midge or mayfly nymph below an indicator, with shot to get them down
Perfection loop · surgeon's / blood knot · improved clinchFloating line → tapered leader → fine tippet (5X to 6X) → a single dry or emerger matched to the hatch, dressed with floatant
Perfection loop · surgeon's / blood knot · improved clinchFloating line (add a sink tip or poly leader) → short stout leader (0X to 2X) → a weighted streamer, cast tight to the bank and stripped back
Perfection loop · improved clinchWhat you need
One 9 ft 5-weight outfit and a floating line cover nymph and dry fly all over the river. Add a sink tip and a short stout leader for streamers (a 6-weight helps there and in wind).
The knots
| Knot | Ties | Used by |
|---|---|---|
| Perfection loop | A neat loop in the leader butt, for loop-to-loop to the fly line. | Leader to fly line |
| Surgeon's knot | Joins tippet to leader, two lines of similar size. | Tippet to leader |
| Blood knot | The traditional line-to-line join for leader and tippet. | Tippet to leader |
| Improved clinch | Ties the fly (and a tippet ring) to the tippet. | The fly and tippet rings |
Learn the improved clinch first for the fly. Use a surgeon's or blood knot to add tippet, and a perfection loop in the leader butt for the loop-to-loop. Wet every knot before you pull it tight.
This one page is the printable I take to the water.
Give me an email and I will show it to you, ready to print. A one-page reference: what's on by month, the licence and rules, a rig for every fish, the shared tackle box and the knots.
I'll send you the cheat sheet, and email you when I add a new place to fish. Nothing else.