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Fly Fishing Rocky Mountain National Park

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Working in a fly shop, I often hear from friends, customers and clients about trips to exciting destinations with fabulous fishing. The stories are often about wonderful western tailwaters like the Gray Reef, the Yampa, the Green and the Bighorn. I’ve heard all about steelhead fishing in British Columbia and Great Lakes tributaries. I’ve been regaled with tales of ten-pound bones and big-shouldered permit on Andros Island flats. And then there are the truly exotic once-in-a-lifetime places like Mongolia and Kamchatka, with fish as big and wild and unknown as the names of the places themselves. I listen, and I dream.

Small creeks abound in RMNP

But then I wake up and realize that I have some of the best fishing in the Unites States, in one of the most beautiful places in the world, right in my backyard. It’s called Rocky Mountain National Park(RMNP). Those of us who partake of its beauty and fish there regularly just call it The Park.If you hang out for any time at all in a northern Front Range fly shop, you’ll eventually hear an exchange that goes like this: “Headin’out?”“Yeah.”“Where ya goin’?”“The Park.”Or you might hear a slightly different version-“Been fishin?”“Yeah.”Where’dja go?”“The Park.”This cryptic code means, in the first case, “I’m going to go catch a bunch of fish.”and in the second case “I caught a bunch of fish.”

Dick in his natural environment

What can you expect when fishing the Park? First of all, expect small waters. Most of the creeks and streams flow in waterways that are 50 feet wide or less that run full only during the late spring/early summer snowmelt. Post-runoff, some stretches of a stream may be 40 feet wide and 6 inches deep, and other stretches may be compressed into deeper runs and holes that are only 10 to 20 feet wide. You’ll also find lots of tiny streams less than 6 feet wide, especially at higher altitudes. As the season progresses, streams become narrower and shallower, until that once 40-foot wide stream is reduced to a 10-foot wide pocket-studded run. Most of the lakes are relatively small - just a few acres in size. Some are very deep, but most are fairly shallow.

Next, expect small fish. Most of what you catch will range between 8 and 12 inches. But that doesn’t mean there aren’t big fish. I regularly see fish over 18 inches, and a brown that I estimated at more than 24 inches chased a smaller fish that I had hooked in a10 foot wide stream. I also saw a 26 inch brown caught in a small lake that is fished regularly for its eager population of small brookies, right next to a picnic ground with a large parking area. A friend caught a 20+”brown in a blown-out beaver pond in a stream that is rarely more than 15 feet wide even during the runoff period. No matter the size of the fish, they are all wild reproducing populations; the Park hasn’t been stocked in decades other than to reintroduce the greenback cutt to its native waters.

Finally, expect little fishing pressure. Yes, there are a few places that get hit hard, but most of the Park’s waters see very few fishermen. If you are willing to walk as little as 15 minutes, you can have a stream to yourself without seeing another angler all day. I’m not talking about remote waters; you can find solitary fishing right along some of the most popular trails in the Park. You just have to go a few hundred yards or a half-mile from where you park your truck. Most of the best lake-fishing destinations require a hike of several miles that vary from easy walks to difficult scrambles, but there are productive lakes within an easy one mile hike or less.

One of the owners of our shop, Mike Kruise, when asked for directions on where to fish in the Park often says “Open the map, find a blue line, then go fishing.”Good advice. On the east side of the divide, the Big Thompson River, Glacier Creek, Fall River and, in the southeast corner of the Park, the North St. Vrain River in the Wild Basin area, provide some of the best fishing. West of the divide, the Colorado River and its tributaries are the main attractions.

Guides can help with locations and technique

Seasons of the Park


Streams below 9000 feet start to become fishable in some years as early as late March, when a warm spell begins to melt the ice and snow. By mid-to late April, there is plenty of open water. This early spring period before the runoff begins in earnest can be spectacular. Insects are beginning to stir as the days lengthen, and the fish start to eat with gusto. Tiny (size 18-20) black and brown stoneflies are active. You’ll often see the adults on the snow along streams. Midges and BWOs become available as the weather and the water warm.

Early Spring Patterns

  • San Juan Worms in purple or pink, size 14-16.
  • Copper Johns in red, copper or blue, sizes 14-18.
  • Pheasant Tail, Gold Ribbed Hare’s Ear and Prince nymphs, sizes 14-18.
  • Assorted midge larva, pupae, emergers and dries in size 20 and smaller.
  • Small (size 18-20) dark stonefly dries; a small dark Elk Hair Caddis often works.
  • BWOs or Adams dries, sizes 16-18.
  • Foam hopper patterns such as the Charlie Boy Hopper or Los Alamos Ant, sizes 12-14 for use as the point fly in a dry/dropper rig.

Both dry/dropper or two-nymph rigs with a strike indicator are effective. An excellent setup is a foam hopper with a red Copper John or purple San Juan Worm dropper.

Effective early spring patterns


As the weather and water warm up in May and June, stream flows increase and become off-color as snowmelt reaches its peak. Many anglers put away their gear during this period, but they are missing out on some great fishing. High water and fast currents concentrate the fish in soft water along the edges of streams and behind obstructions where they find cover as well as relief from the heavy water. Even during the unusually high volume and long-lasting runoff in 2008, we caught plenty of fish. Focus on the soft water areas and fish two-nymph setups. If fish start to hit your strike indicator, switch to a dry/dropper rig. As my friend Frank Drummond says, “If the fish are hitting your indicator, it indicates that you should be using a dry fly.”While you won’t see many hatches this time of year, you’ll see some, including the small stones and BWOs noted above, as well as a few caddis, especially in quiet backwaters and eddies.

Runoff Patterns

  • All of the patterns above, plus
  • Caddis larvae and pupae- Barr’s Graphic Caddis, Lafontaine Deep Sparkle Pupa, and cased and uncased caddis larva patterns are good choices.
  • Caddis dries and emergers such as the Elk Hair Caddis, E/C Caddis or Tabou Caddis Emerger.

Nymphing is usually the most effective approach during runoff, but dry/dropper setups are sometimes effective, especially during hatches.

A Colorado grand slam



Effective runoff patterns

Summer and Fall

If you love dry fly fishing, as I do, the Park is heaven on earth from the end of runoff until November. As summer weather and temperatures arrive, even the highest lakes and streams open. Ice-off on the high lakes means hungry fish. Sight-fishing to cruising greenbacks with tiny midge patterns provides heart- pounding action.

Hatches along streams include several reliable mayflies-Red Quills, Green Drakes, and PMDs abound. Caddis come alive, and larger stoneflies become more plentiful. Tiny chartreuse Yellow Sallies flit around like blurry little fuzzballs. The fish are, as they say, “looking up.”While some days require a strict match the hatch approach, most of the time anything that floats will be hammered.

Summer and Fall Patterns

  • Adams or Parachute Adams, sizes 14-18.
  • Red Quill, PMD and BWO mayfly dries and spent spinners, sizes 14-18.
  • PMD and BWO emerger patterns such as the Barr Emerger, sizes 16-18.
  • Green Drake, sizes 10-14.
  • -Caddis-Elk Hair Caddis, E/C Caddis and X-Caddis are excellent, sizes 14-16.
  • Caddis pupae and emergers-Graphic Caddis, Deep Sparkle Pupa and Tabou Caddis Emerger, sizes 14-18.
  • Terrestrials-foam hoppers, ants and beetles, sizes 12-18.
  • Attractor dries such as Humpies, Royal Wulffs and Stimulators sizes 12-18.
  • Standard nymph patterns such as the Hare’s Ear, Pheasant Tail, Copper John and Prince, sizes 14-18.

-Lakes demand tiny (size 20-24) midge dries and emergers. Griffith’s Gnats and Adams are often good producers.

Effective summer and fall patterns

Fish a dry by itself, or if that’s not working, use a dry/dropper combination with an emerger or small nymph. My standard setup isa size 16 Parachute Adams trailing a mayfly or caddis emerger, or, in late summer, a Los Alamos Ant or beetle pattern. A dry/dropper setup is done by attaching a nymph to the hook bend of a dry fly, about 12 inches apart.

Dry/dropper setup

Weather and Other Hazards

Weather in the Park must be respected.

  • Late fall and early spring may bring sudden snow, sleet or rain storms. Be prepared by wearing layers that allow you to adjust to changing conditions.
  • Summer means thunderstorms. Know what to do during a storm, especially above timberline; get to a lower altitude if it can be done safely.
  • Always carry a light rain jacket and wear a hat.
  • Beware of altitude sickness and sunburn; always wear sunglasses for eye protection.
  • Take plenty of water, or better yet, use a water bottle with a built- in filter.
  • Carry a small survival kit, especially if you fish by yourself.
  • Let somebody know where you are going and when you expect to return, and ask them to call the Park administration if you don’t call by a pre-arranged time.

Fall fly fishing in RMNP


Because many of the tourists who fish the Park are not aware of the fishing regulations, there are a lot of unintentional violations. Unfortunately, the Park is not very effective in making the regulations known; visitors do not receive a copy of the RMNP fishing regulations when entering the park unless they ask for them. There are no signs explaining the regs. Individual rangers I’ve encountered are very helpful and effective in enforcement, however. I routinely carry a copy or two of the RMNP fishing regulations in my vest, and I’ve had many occasions to pass them along. I’ve also helped many spin-fishing anglers by sharing my flies and strike indicators and showing them how to use their spinning gear as an effective nymph rig.

The basic regulations as of this writing are:

  • All greenback cutthroat must be returned to the water immediately.
  • Fishing is limited to barbless flies and lures.This does not include:
  • (a) any hand moldable material designed to attract fish by the sense of taste or smell;
  • (b) any device to which scents or smell attractants have been externally applied;
  • (c) molded plastic devices less than one and one-half inch in length;
  • (d) foods;
  • (e) traditional organic baits such as worms, grubs, crickets, leeches, minnows, and fish eggs; and
  • (f) manufactured baits such as imitation fish eggs, dough baits, or stink baits.
  • Children 12 years of age or under may use worms or preserved fish eggs in all park waters open to fishing except those designated as catch-and release areas.
  • No more than two flies may be used at one time.

 Additional Resources

In addition to the map you receive when you enter the Park, the serious Park angler should have a copy of Trails Illustrated’s National Geographic RMNP map. Todd Hosman’s Fly Fishing Rocky Mountain National Park is the authority on RMNP angling. I’ll probably continue to dream about Ulan Bator and Ft. Smith and Pesca Maya and Andros and such places, but when it comes to my own fishing adventures, you’ll most often find me with my 2-wt somewhere on Glacier.

Tight Lines,

Dick Shinton

Please visit for more great info about fly fishing and Rocky Mountain National Park.


© 2024 Dick Shinton
This article was published first in High Country Angler Magazine in 2009, Rocky Mountain Fly Fisher added additional information with the authorís permission, Fish Explorer edited the article to fit their formatting, Share This! This was created in the spirit of passing on a passion for the sport and helping others find fishing success. Please share this free resource with as many people as you wish.
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