Small Streams in Yellowstone Park

Yellowstone Park’s small streams and creeks are not famous and their trout are usually small. A 12-incher is a big one on most streams on an average day, but there are hundreds of miles of small streams, ranging in character from rough-and-tumble creeks tumbling vertically down mountains through boulder gardens to classic riffle-pool trout streams to undercut, meandering meadow streams where even the eight-inchers bolt if you throw a shadow on the water. These streams, even some near the road, usually offer visiting anglers something in short supply on easy-to-reach sections of the region’s larger, more famous rivers: solitude.

Even if you’re here to fish famous water, I suggest you take some time off to fish a little creek. They’re often very good on late summer afternoons when larger rivers might be tough, especially when they flow in canyons or under trees. They’re also just pretty and fun to fish, especially using dry flies.

Each small stream is unique, but for purposes of this guide I’ve cut them into five categories:

• Creeks dominated by brook trout tend to be the easiest and fish comparably no matter their character.
• Meadow streams draining the park’s central plateau that don’t hold brook trout, or at least few of them, are much more difficult to fish, but generally easy to approach via flat hikes of a few hundred yards to a couple miles.
• Lamar tributaries beside Soda Butte and Slough Creeks all hold cutthroat trout and are intermediate in difficulty and access.
• Rough mountain creeks holding trout other than brookies are generally very hard to access but can hold some good trout, mostly cutthroats.
• Firehole River “refuge” tributaries are most notable for holding small numbers of potentially very large Firehole fish that run up seeking refuge from summer heat. These fish and streams are very difficult.

Another category is worth mentioning: permanently closed streams. Most Yellowstone River tributaries between Yellowstone Lake and Chittenden Bridge fit into this category. The tribs to Yellowstone Lake (with the exception of Pelican Creek) are in many cases open to fishing, but they aren’t worth your time, either.

• We run many Walk & Wade Guided Trips on small streams in Yellowstone Park, especially when we’re guiding beginners and any anglers interested in unusual fish and waters without crowds, rather than the largest possible fish.

Fishing Small Streams in YNP

Brook Trout Creeks

Brook trout creeks are any creeks where brook trout comprise the majority or entirety of the trout population. Regardless of character, these creeks all tend to fish about the same. Most brook trout creeks are located above waterfalls and thus could not be populated from areas downstream. Many brook trout creeks are in the Gardner River System, but there are some in the Yellowstone, Firehole, and Lewis River Systems as well. In fact the upper Firehole and upper Gardner Rivers are basically brook trout creeks in their own right.

In the Rockies, brook trout tend to overpopulate and stunt themselves. As such, almost all brook trout creeks in Yellowstone Park hold fish that seldom get larger than your hand, and finger-length fish are common. These fish are exceptionally aggressive and reward anglers who do almost anything right. As such, they’re most suitable for beginners, especially kids and anyone who just wants to get a taste of fly fishing, rather than really trying to learn techniques.

Most brook trout creeks fish best from sometime in the latter half of June or first week of July through mid-August. A few continue to fish well until Labor Day. After that, fishing gets very hard due to cold, low water.

In addition to the difficulty of the season, many brook trout creeks near Gardiner see intense guided pressure since they’re so easy for beginners. As such, it’s important to fish some combination of rough water, small water (the tiniest brookie creeks are actually of the most interest to experienced anglers—break out your one-weight rod!), and water that’s at least a mile off the road. The more of these you can combine, the better the fishing is likely to be.

Meadow Streams Draining the Park’s Central Plateau

Meadow streams draining the park’s central plateau tend to be gentle and often have a slight tannic stain from the pine forests lining the hillsides surrounding these creeks. These streams may hold any trout species (though those that hold brookies fish like other brookie streams). The upper Gibbon River qualifies as one of these streams, and it even holds Arctic grayling.

Most streams on the central plateau are accessible by fairly short, flat hikes, and the only hazards are the hordes of mosquitoes which often live in the swampy areas through which these streams often flow.

Fishing is often more challenging on small meadow streams on the central plateau than it is on most small streams. Slow water breeds spooky fish, even when these fish are small. And most of the fish are small. The central plateau is at over 7000 feet elevation, so the growing season and food base in these streams are both lower than many other creeks and large rivers.

Because of the flat gradient of these streams and the facts that most of these streams drain low mountains and many have lakes in the drainage, central plateau streams come into shape earlier than many small streams, usually in mid–late June. They fish best in July, but can continue to fish into September. That said, but mid-August the trout can be exceptionally spooky in these streams, even when they’re hand-size.

All of the above means that central plateau streams are generally most suited to anglers with some experience who don’t wish to deal with rough water or the crowds of anglers common on larger streams and rivers, especially anglers who don’t mind a mild hike but might not want or be up for an aggressive one.

Lamar Drainage Tributaries

Lamar Drainage tributaries—primarily Pebble Creek, which feeds Soda Butte, and all small hike-in tributaries of the Lamar— tend to have rocky beds and flow as riffle-pool streams. There’s usually some pocket water and lots of wood, and some streams (especially Pebble) take on a meadow character in spots.

These streams all hold cutthroat trout. The resident cutts seldom exceed fourteen inches and are often smaller, but all of these streams also receive spawning runs from their parent streams in early summer. These fish average 14–18 inches and usually remain for several weeks after spawning ends in early July, into mid-August in some cases.

The post-spawn cutthroats are one factor that makes Lamar tributaries interesting. The other is that these creeks tend to see similar hatches as the larger streams in the basin. Some of the best Green Drake hatches I’ve seen have been on Lamar tributaries, for example.

The downside of these streams is that all except lower Pebble Creek require significant hikes to access. Many tributaries in the upper Lamar system (upstream from Cache Creek) require multi-day backpacking or horseback trips to reach. This makes them attractive targets for anglers looking for a long backpacking trip, but basically useless for everyone else.

All Lamar System tributaries fish best in July and early August. By September, all are getting low, and most or all larger trout will have moved back to the Lamar. These streams also get very cold at night since they lack any geyser discharge or lakes at their heads, so morning fishing in particular falls off a cliff as early as August 20.

Rough Mountain Streams

Rough mountain streams are the “classic” trout creeks. These are high-gradient, fast, turbulent streams with steep banks. Getting around is usually more difficult than getting the trout to bite.

Despite their “classic” nature, there actually aren’t many such creeks in Yellowstone Park. For one thing, most of the central part of the park is relatively level, so there just isn’t enough gradient for “rough and tumble” streams. For another, most creeks that have a rough character hold brook trout and as such fish like other brookie creeks; they’re just rougher to traverse.

Most of the steep creeks that do fit this bill are in the Yellowstone System, but there are others that feed the Gardner and Lamar (Buffalo Creek, which is actually undergoing a fisheries project to remove non-native rainbow trout and as such is not a worthwhile fishery right now). Most hold cutthroat trout or rainbow-cutthroat hybrids, but some hold other trout. Except where they pass close to or under roads, all of these creeks are difficult to access. They require some combination of hiking (usually with a significant elevation gain/loss component) and rough scrambling/wading. This tends to shed crowds except where there are popular trails nearby.

These creeks all fish best in late July and August. They’re often too high to wade before that, and can get too low and cold thereafter. Because of their turbulent nature, the trout in these creeks are not spooky. They will usually strike any well-presented attractor fly or grasshopper imitation. On the other hand, casts need to be accurate and well-controlled, so these creeks usually are not suitable for total beginners.

If you like this sort of creek, also look at creeks feeding the Yellowstone north of the park boundary. These creeks almost all fit this bill, as do many feeding other rivers in the area that are beyond day-trip range from Gardiner.

Firehole River Refuge Tributaries

Many small streams are ideal for beginners and novices. Firehole Refuge tribs are anything but.

These are creeks that feed the Firehole River without suffering significant hot spring discharge. Since they remain cold where they run into the Firehole, these creeks provide thermal refuges in midsummer for trout—particularly larger trout running 14–20+ inches—that cannot survive the high water temperatures the Firehole endures in midsummer. These are big fish in small water, and they’re nervous because of it.

All tribs that fit this bill have a gentle meadow character near their mouths, which doesn’t help matters. Glassy-smooth water makes for spooky fish even when they aren’t coming from a much larger stream. All of these factors combine to make for some of the hardest trout in Yellowstone Park to avoid spooking. They’re usually not all that hard to fool, since they’re seldom selective towards specific flies, but they are exceptionally wary. Only advanced and expert anglers should think about fishing these creeks.

Even for experts, this is hands-and-knees fishing using long (12–15 foot) leaders and 5X or smaller tippets. Long casts over grass to sighted fish are more common than fishing the water. Small nymphs, ants, and beetles are usually better than anything more ostentatious. A handful of fish qualifies as a good day, but these fish might be far larger than you’d expect from a small stream.

Because they depend on summer migrants from the Firehole, all refuge streams fish best from mid-July through August 20 when water temps on the Firehole are highest. Otherwise, they fish like other small streams with similar character. The Little Firehole discussed in the next section is basically a rough and tumble mountain creek without its run-up fish, for example.

YNP Small Streams – Some Places to Start

I’m not going to hotspot secret little streams on the Internet. I used to, and I learned my lesson. Instead I’ll suggest that finding good small creeks with a map and an exploratory spirit is part of the fun.

To get you started, here are five example creeks, one for each category, and a map pointing you towards them. None of these are secrets, and none have been for a while, but they all still fish well.

Blacktail Deer Creek – Brook Trout Creek

Blacktail Deer Creek is a Yellowstone River tributary east of Mammoth, the Gardner River, and Lava Creek. The nearby Blacktail Ponds drain into the creek via a swampy area. Waterfalls immediately upstream from the Yellowstone confluence prevented upstream migration by cutthroat. The fishless creek was stocked with brookies in the late 1800s. Nowadays the creek sees heavy guide pressure, usually between a mile and half a mile from the road.

Blacktail averages about ten feet wide, though if you find a beaver pond it can get much wider. It’s generally an approachable riffle-pool stream, though there are some areas of pocket water where the creek cuts through hills, and the closer you get to the Yellowstone, the steeper the creek gets. Near the Mammoth-Tower Road crossing, the creek is absolutely choked with willow bushes. In these areas, just getting into the stream is more than a chore. It’s particularly bad upstream of the road, which is one reason why most pressure occurs downstream. Walk downstream on the Blacktail Trail for twenty minutes, then cut over to the creek. When the fishing slows, you’re getting too close to the road.

Standard attractor dry-dropper combos are all you need on Blacktail. A #14 Trude trailing a #18 beadhead Prince is a good combo. Blacktail can start fishing as early as June 20 in drought years, but the best fishing is probably in early August, a bit later than many brookie streams.

Nez Perce Creek – Stream Draining the Central Plateau

Nez Perce is the Firehole’s largest tributary and has a similar character to the Firehole. It flows west off the central plateau to join the Firehole near Fountain Flats. Lots of geyser activity and low-quality shallow riffles and lava rock near its mouth limit the creek’s use as a refuge stream. Instead the focus is a couple miles upstream where the creek is narrower, deeper, and flows between undercut banks. Here the population is a mix of browns, brookies, and rainbows, in about that order. Most are under 12 inches, but there may be a few surprises.

Since it is a gentle meadow stream for the most part, Nez Perce demands cautious approaches and casts. PMD, Green Drake, caddis, and Yellow Sally hatches are possible, but smaller attractor dry-dropper combos such as a Wulff Cripple trailing a Pheasant Tail usually work fine. The important thing is to avoid making splashy casts or throwing your shadow on a pool before fishing it. In late summer, small hoppers and beetles are also good bets.

The creek fishes best in July. Access Nez Perce via the Mary Mountain Trail. The good water begins about where the trail comes alongside the creek. Note that access to the creek upstream from the Madison-Old Faithful Road (that is to say, the water worth a damn) is usually closed in June due to bear activity. Make noise and carry bear spray here. A hiker was killed by a grizzly a few years ago along Nez Perce.

Pebble Creek – Lamar System Tributary

Pebble Creek is the largest tributary to Soda Butte Creek in Yellowstone Park. It drains the first valley west of Soda Butte’s before cutting through a nasty canyon and joining Soda Butte in the middle of Round Prairie. It holds cutthroat trout, including some nice ones in both its upper and lower reaches.

The creek has three characters. Upper reaches resemble Soda Butte or Slough Creek’s meadows in miniature. This is the best stretch, and is home to some nice cutthroats over 15 inches minus the crowds on its parent stream. That said, accessing this stretch requires a horrific climb over the first mountain ridge. The hike’s only a couple miles, but you’re climbing hard for the first half. Access this water via the Warm Creek Trailhead. Use similar tactics as on the Lamar or Soda Butte, with a higher reliance on ants, beetles, and small hoppers and less reliance on aquatic insects. This water fishes best in late July and August.

In its canyon, upstream from Pebble Creek Campground near the Northeast Entrance Road, Pebble Creek is a small rough and tumble pocket water stream. Travel along the banks is often treacherous. While pressure is heavy near the campground, the trout are small: most run under 9 inches. Fish attractor dry/dropper combos if you fish here. Access this water by walking upstream from the campground. The south end of the Pebble Creek Trail is not very useful, as it follows the ridge east of the creek and scrambling down in the canyon is a challenge at best.

Downstream from Pebble Creek Campground, Pebble Creek enters Round Prairie and transitions into a spawning and nursery stream for Soda Butte Fish. The average fish measure less than six inches, but much larger fish from Soda Butte may remain after spawning, with most returning to Soda Butte by early August. These fish can be quite spooky. Match hatches that are occurring on Soda Butte or fish hopper-dropper combos. This water sees heavy pressure, particularly since it usually stays clear even when Soda Butte gets muddy. Access this area by walking across Round Prairie.

Hellroaring Creek – Rough Mountain Stream

Hellroaring is the Yellowstone’s largest tributary in the park that qualifies as a “creek” instead of a river. It drains the valley west of Slough Creek and feeds into the Yellowstone from the north. In Hellroaring Basin north of the park this is a small meadow stream, but inside the park it’s a hefty pocket water stream 25+ feet across that can be very difficult to wade prior to late July. It holds a mixed bag of cutthroat, rainbow, and hybrid trout. The largest fish are big post-spawn cutthroats up from the Yellowstone that might reach 20 inches on occasion but average more like 14–16. These fish are most common in the bottom mile of creek, basically from where the Yellowstone River Trail crosses down to the Yellowstone. The average resident fish are more like 10–12 inches.

While the Salmonfly and other hatches from the Yellowstone sometimes spill into the creek, it’s seldom necessary to fish anything but medium-sized attractor dry/dropper combos. Think a #10 gold Chubby Chernobyl with a #16 tunghead Prince or Yellow Sally nymph. The further upstream you get on the creek, the more likely you want to shift to slightly smaller flies. Grasshoppers are also a good bet here in late summer.

Access Hellroaring via the Yellowstone River Trail. Use the Hellroaring Trailhead. It’s 2.1 miles to the creek, the first mile an 800-foot descent to the river and the remainder of the trip a hot, dry, but level hike across a dry grass and sage meadow. The trail crosses the creek a mile upstream from the Yellowstone and is followed on both sides by trails down to the mouth and up to a footbridge over the creek a couple miles upstream (the bridge must be used to cross the creek before at least mid-July). The trail on the east side of the creek continues upstream to the park boundary and beyond. While the lower creek can be fished as a day trip, numerous backcountry campsites are also available, and see pretty heavy use.

Hellroaring fishes best in July and August, but it’s a big enough stream to continue fishing in the afternoon until mid-September.

Little Firehole River – Firehole Refuge Tributary

In its upper reaches, above Mystic Falls and in the canyon below it, the Little Firehole is a small rough and tumble mountain creek home to a mixed bag of trout. Near its confluence with the Firehole at Biscuit Basin, it’s a slow, deep meadow stream about 15 feet wide upstream from its tributary Iron Spring Creek and more like 25–30 feet downstream of it (Iron Spring Creek enters right above the Little’s confluence with the Firehole). In this lower reach, it holds a few small resident fish but also some absolute monsters up from the Firehole. The largest trout I’ve ever seen in the Firehole System was in the Little Firehole. It was a rainbow I estimate at 24 inches. I made one cast and the trout laughed at me and disappeared.

This is strictly expert water. Fish a 12–15 foot leader tapered to 5X or 6X. Use a beetle or foam hopper with a Pheasant Tail or similar dropper, or just go with the nymph and a bit of white yarn for your indicator. It’s seldom worth blind-casting. Instead, spot & stalk. This is more like hunting than fishing. Firehole refuge tribs always fish like this, but even more so in the lower Little Firehole. Don’t expect many fish, but if you get a couple, count yourself blessed.

Access the Little Firehole from Biscuit Basin. Cross the footbridge over the Firehole, then walk upstream until you reach the Little Firehole. Work upstream. This water is best from July 10 through August 20, basically when the Firehole is way too warm for trout comfort. I suggest letting the Little Firehole be during drought years, since the Firehole refugees need all the help they can get in such conditions.

Insect Hatches & Other Prey

It is seldom necessary to precisely match insect hatches on small streams in Yellowstone Park except when fishing Lamar River tributaries, which often see Green Drake hatches in the summer.

Rather than precisely matching hatches, fish attractor dries and small or medium-sized terrestrials trailing beadhead nymphs.

In general, the smaller and gentler the stream, the more important it is to fish small and sparse flies instead of bulky ones. A Parachute Adams trailing a Pheasant Tail is a better combo on gentle streams than a Chubby Chernobyl with a big Prince, for example.

On brook trout creeks, you almost always get away with your preferred midsize attractor combo: Trudes and Wulffs trailing a #16 beadhead Prince, for example.

Top 10 Flies for YNP Small Streams

1. Coachman Trude, #12–16
2. Purple Hazy Cripple, #14–18
3. Royal Wulff or Royal Wulff Cripple, #12–16
4. Tan X-Caddis, #14–16
5. Cinnamon Flying Ant, #16
6. Pink Bob Hopper, #14
7. Hi-Viz Micro Chubby Chernobyl, Gold, #14
8. Beadhead Prince, #16–18
9. Beadhead Flashback Pheasant Tail, #16–18
10. Copper John (Red or Copper), #16

The patterns above are less-suited to Lamar Drainage tributaries. There, add some Green Drake patterns ranging from #12 Parachute Adams if you’re hiking far into the backcountry to the same flies you’d use on the Lamar or Soda Butte Creek if you’re fishing Pebble Creek or other streams within day-trip range of the road.