Fly Fishing Middle Montana: Roads, Ranches, and (Vacant) Rivers

You might have heard about the recent crowding on the Madison River. It has been a hot topic in that state as Montana Fish, Wildlife & Parks works through how to manage the river for increased user satisfaction, economics, and to do what’s best for the river and trout. This increased traffic has occurred on many fisheries nationwide since the pandemic hit in 2020. 

There’s no debating the greatness and resilience of the Madison, Yellowstone, Missouri, and other famous rivers, but something’s gotta give—they need a break. There’s also no debating the greatness of countless off-the-radar trout fisheries in Montana. Using these places can be a step toward reducing crowding on the famous life-list must-fish rivers throughout the West.

One such area worthy of exploration is what I call “middle Montana.” While the streams in this region don’t boast the fish-per-mile statistics of the Bighorn or Yellowstone, they offer a different but equal appeal. Actual solitude, large and/or native trout, and an envy-inducing experience that’s different from most other anglers’ are just a few of the calling cards of this part of Montana.

Below are profiles of five of my favorite central Montana rivers, each with their own beauty, solitude, and trout. All of them are in the Missouri River drainage from Great Falls to Fort Peck Reservoir, and all should be on your radar.

Fly Fishing the Musselshell River

Montana’s Musselshell River is a great example of a river out-of-staters might never have heard of. It starts as two small forks that wind through desolate ranchland and national forest, before each enters its own water storage reservoir. The North Fork of the Musselshell River tumbles out of the Little Belt Mountains near White Sulphur Springs until it flows into Bair Reservoir on private land. The South Fork snakes across dry ranchland along Montana Route 294 prior to being diverted into Martinsdale Reservoir near the reservoir’s namesake town.

The forks merge just east of Martinsdale, and the main stem shimmies its circuitous path alongside U.S. Highway 12 for about 350 miles until it flows into Fort Peck Reservoir. Each mile downstream of Martinsdale gets more and more marginal for trout habitat, especially in warm and dry years. Because it drains such a large area, it’s also especially prone to major floods. For the most part, in this day of climate change, anglers will want to focus their trout fishing upstream of the town of Two Dot, though errant browns are found all the way down to around Roundup, about 150 river miles from Martinsdale.

Nowadays it hosts only browns, rainbows, and whitefish. The tailwater sections on the forks offer good fishing for browns that get larger than you’d expect, and hopper season can be productive on good water years throughout the trout water. Author John Holt wrote of hooking fish on mouse flies made of horsehair (tied on the spot, clipped from live horses, so he says). And streamers can be hot on overcast days. Don’t be surprised to find a smallmouth bass in the marginal water, and there are northern pike and carp (and a variety of other species) downstream of Roundup.

There are a couple of official FWP fishing access sites along this stretch of the ’Shell: Selkirk FAS where the forks come together near Martinsdale, and Harlowton FAS just downstream of the bridge in Harlowton, Montana. There are also a few public-road bridges where anglers and can hop into the river, staying within the high-water mark.

Fly Fishing Big Spring Creek

Big Spring Creek near the hub of Lewistown has excellent small-stream trouting in a true coldwater environment. It is probably the best known of the rivers listed here, having received some media attention over the years. You might see a bit more angling pressure than on other area streams (especially upstream of downtown Lewistown), but the fishing rarely seems to suffer.

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It starts as a large natural spring just upstream of Lewistown where FWP has a hatchery. The spring itself is one of the world’s largest, bubbling up at over 50,000 gallons per minute. The creek is relatively short at only about 30 miles total, and it dumps into the Judith River northwest of town. The lowest 10 or so miles offer the worst trout habitat and the least access.

It often fishes great just upstream of downtown Lewistown at the Brewery Flats fishing access site, which has lots of fishable water alongside a well-maintained trail system. The riverbed is actually channelized and paved (seriously, with concrete) for a stretch near downtown, but regains wild character downstream near the Lazy KB access.

The browns and rainbows get up to about 16 inches, with some larger specimens. There are quite a few public accesses to this brief creek, including one at the headwaters hatchery called Hatchery FAS, Spring Creek FAS, Brewery Flats, Lazy KB, Carroll Trail, Reed & Bowles, and finally Hruska at Scott Crossing Road.

Big Spring tends to have a wider variety of hatches by area standards, with reliable midge, Blue-winged Olive, Pale Morning Dun, and caddis hatches in their seasons. Hoppers and streamers, again in their seasons, can also produce good results.

Its flows are less affected by the whims of the seasons and air temperatures than a freestone stream because its source is a constant-temperature spring. As such, it is often fishable every month of the year, especially near its source.

It tumbles a bit faster than many spring creeks, therefore is not often as technical a fishery as other spring creeks such as the famous ones 100 or so miles southwest of here in Montana’s Paradise Valley.

There are also a couple of upper-river tributaries that offer trout, and a couple of fishable reservoirs within the drainage.

Fly Fishing the Judith River

The Judith River also forms in the Little Belt Mountains where the Middle Fork joins the South Fork. Both forks actually headwater within a few miles of the North Fork of the Musselshell, but both flow northeast rather than southeast (like the Musselshell). It is these upper portions of the Judith system that offer most of the best trout fishing.

This is one of the only places in this area that still has a native population of westslope cutthroat trout.

The beautiful Middle Fork of the Judith has been the subject of habitat restoration work by Montana Trout Unlimited. MTU has worked with the Helena-Lewis and Clark National Forest to reroute roads that cross the Middle Fork, thereby reducing the degradation that came with vehicles crossing the river.

The middle stretch of the main stem Judith River, from the town of Hobson to about the mouth of Willow Creek, is largely inaccessible except for a handful of gravel-road bridges and a wildlife management area. But it’s also not great fish habitat currently, being mostly managed for agriculture.

The lower Judith River, however, flows through a lush cottonwood lowland surrounded by uneven sandstone ridges. There, Montana FWP has surveyed northern pike up to 37 inches (roughly 13 pounds), walleyes up to 26 inches, channel catfish up to 33 inches, some big rainbow trout (more on that later), and a smattering of smallmouth bass, brown trout, carp, goldeye, sauger, stonecats, burbot, and myriad other rough fish. Regarding those rainbows, there is a small run of big Fort Peck Reservoir winter-spawning rainbow trout that migrates through the lower Judith in October and early November, and outmigrates from late January through March.

“They range from 18 inches and maybe 2-plus pounds to 26 inches and 8.7 pounds,” Clint Smith, a Lewistown area FWP fisheries biologist, said of the rainbows. “Most of the fish we’ve tagged have been in the 22- to 26-inch range.” There are very few fish in this run. Smith estimates fewer than one of these size trout per mile, so it’s somewhat like a steelhead run, but “Folks do catch these fish occasionally,” said Smith.

When this run is not happening, fly fishers can still target the aforementioned species in the lower sections of the Judith. And there are rumors of rare but large brown trout.

Don’t immediately turn up your nose at goldeye­—this native Montanan can provide hours of non-traditional fun for fly anglers of all skill levels on drys, nymphs, and streamers.

A nonprofit prairie restoration organizations called American Prairie owns a sizable chunk of land on the lower Judith called the PN Ranch, which offers public access along with a couple of rentable yurts.

The Missouri River near the mouth of the Judith (known as Judith Landing) is in the middle of the majestic Upper Missouri River Breaks National Monument and has good fishing for northern pike, walleyes, and ubiquitous goldeyes, among other species (especially if you feel like packing your spinning rod and some crankbaits).

Fly Fishing Belt Creek

Belt Creek is truly among the most beautiful trout streams in Montana. Its gin-clear water flows through a steep and stunning canyon, and it abounds with access. All of Belt Creek is trout water, but today only the stuff above Sluice Boxes State Park has a reliable population of native westslope cutts.

It starts its journey near the small town of Neihart in the Helena-Lewis and Clark National Forest along U.S. Highway 89. There is abundant roadside access in this upper section, where small cutthroats enjoy Belt’s swift currents and throw caution to the wind in attacking dry flies.

From there, Belt Creek cuts west and runs through the unreal canyon of Sluice Boxes State Park. A rustic trail follows the creek here, but there are cliffed-out sections and some serious terrain that make access challenging in spots. You can float through the canyon in small craft, but inexperienced oarsmen might want to think twice during periods of high flow. Camping is allowed at the state park, but a state backcountry permit is required.

The state park is where Belt Creek transitions from small cutthroat water to a wider river capable of hosting good-sized brown and rainbow trout. And the very bottom of Sluice Boxes State Park does offer good fishing and access. Though there is not much public access downstream of the state park, there is lots of water to get lost on. And anglers could tie into something noteworthy from one of the public-road bridges, as brown and rainbow trout remain in the river to its mouth.

Belt Creek’s hatches are not super heavy, but its trout regardless look to the surface with regularity. The water often runs very clear and quite swift, so achieving passable dry-fly drifts can be challenging, but the rewards can be great.

Fly Fishing the Marias River

The Marias River recently gained a great deal of press when Montana’s 50-plus-year-old state brown trout record fell to a local spin angler in March of 2021. The fisherman landed a 32.42-pound brown in the dusk light on an undisclosed section of the river. The Marias already had a growing reputation for decent-sized brown trout below Tiber Dam, but this fish landed the Marias squarely in many anglers’ sights.

That said, it’s still in a remote part of a relatively unpopulated state, so fishing pressure won’t ever get to Madison River levels. Just don’t expect to be the first in line at the boat ramp anymore.

Floating the tailwater section is the most common method of approaching the Marias. Wade fishing the public water directly below the dam is possible, but downstream of that, a boat provides the most practical access. Sanford Park, just below Tiber Dam, has a nice campground and boat ramp, and there’s a takeout about 5 miles downstream, at Pugsley Bridge.

Only the bottom-draw tailwater section is reliable trout water. The lower end runs through arid agricultural properties. Alongside the browns and rainbows are good numbers of carp and whitefish, and occasional northern pike. Despite its reputation for big trout, they are not easy to catch.

Streamers are often the preferred tackle here, but excellent PMD and caddis hatches occur throughout the summer, and Tiber Dam keeps flows cold year-round.

Above Tiber Reservoir (aka Lake Elwell), anglers might find a few trout, but it’s again mostly a warmwater fishery despite being nearer the Rocky Mountain Front than the tailwater section. It’s also largely inaccessible.

Understanding Montana's Stream Access Law

There are fewer official fishing access sites in this remote part of the state, so understanding the Montana Stream Access Law can be a game changer here. Occasional crotchety ranch hands or landowners might give you grief, but if you’re armed with confidence in Montana’s laws, they cannot legally kick you out.

Montana’s Stream Access Law states that recreationists can use rivers and streams capable of recreational use regardless of streambed ownership, as long as they have accessed the streambed from a public place or with landowner permission. Public places include any sort of public land, official fishing access sites, and bridges on public roads that cross rivers.

Regarding bridge access: There is an easement that stretches 30 feet on either side of the center of any public road—often well beyond the road’s edge—that the public has the right to use despite technically being private property. When this easement crosses over rivers (at bridges), the public is allowed to use that easement to access the stream. From there, users must stay within the high-water marks.

The Fish, Wildlife & Parks “Stream Access in Montana” brochure describes the high-water mark as “the line that water impresses on land by covering it for sufficient time to cause different characteristics below the line, such as deprivation of the soil of substantially all its terrestrial vegetation . . . ” And its “ordinary” high-water mark meaning normal-flow mark, not “annual,” meaning runoff mark. And it’s not within 10 feet, nor 2 feet (both of which I’ve heard anglers say), it’s within it.

One often-overlooked aspect is that notice denying entry to private land must be posted. From the brochure: “. . . a member of the public has the privilege to enter or remain on private land by the explicit permission of the landowner or his agent or by the failure of the landowner to post notice denying entry onto the land. The landowner may revoke the permission by personal communication.” I warn against taking too much advantage of this, lest you find more hassle than fish.

That notice must consist of “written notice or by . . . painting a post, structure or natural object with at least 50 square inches of fluorescent orange paint. In the case of a metal fencepost, the entire post must be painted. This notice must be placed at each outer gate and all normal points of access to the property and wherever a stream crosses an outer boundary line.”

Some other details:

• The law does not address lakes.
• A no-trespassing sign at a bridge on a public road is notice of private property, but does not mean anglers cannot access that stream there.
• River users may portage around man-made obstructions (like fences, irrigation equipment, or junked appliances/vehicles) in the least intrusive manner possible, but this does not address natural barriers such as fallen trees, leaving such instances open to convenient interpretations.

Landowner conflicts often occur on these seldom-waded drainages where ranchers aren’t used to seeing strangers. If challenged, it’s important to remain respectful and cool, even if you see a firearm. Calmly explain that you entered legally, and that you have remained within the high-water marks the entire time (and be sure to have done so). Inquire about what evidence they have (some claim to have trail cams at bridges, etc.) and explain the law. Always try to de-escalate, and never argue too long. No stretch of river is worth risking your life for.

And don’t be afraid to venture beyond the five fisheries listed here—there are many good tributaries and nearby reservoirs in this part of Montana that offer access and trout.

Ground clearance, four-wheel drive, a spare tire, and a full gas tank are always recommended when visiting this area. Check the forecast and road conditions before embarking. A smartphone navigation app like Avenza Maps is also recommended because it doesn’t require an Internet signal, which can be scarce here. And there’s usually a good brewery or memorable dive bar somewhere nearby to cap your day.

Much has been opined about Montana’s famous water becoming crowded lately. It’s time that we anglers fish outside the Treasure State’s box of fame. Poke around a little—you’re likely to come away with some good stories and great fish.

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Joshua Bergan is Fly Fisherman’s digital editor.