Montana Fly Fishing 3 min read

DIY Guide to Fly Fishing the Missouri River in Montana

Ken Sperry

Posted by Ken Sperry

July 10, 2017

Missouri River Montana

The state of Montana is not shy of angling options and fly fishing the Missouri River is top of the list. 45 miles from Helena, Montana is Holter Dam. This dam is the central focus of a 30 to 40 mile stretch of the Missouri River.

Many locals and well-traveled fly fishing connoisseurs consider it one of the best trout fishing sections of water in Montana. Possibly the lower 48 states. A short drive off of I-15 will place you at this fishing hotbed.

About Missouri River

From the Holter Dam to the city of Cascade runs the Missouri River, and this 40 mile stretch is home to approximately 3,500 to 5,500 fish per mile. Rainbows and Browns aplenty, with many of them exceeding 16 inches, it is no wonder this section of the Missouri has the reputation that it does.

Rainbow trout average between 14-18 inches while the browns measure in a bit larger. Given the dense trout populations and their size, this section of the river is not a destination for the angler seeking solitude.

What you can expect during peak times is wading fly fisherman mingling with drift boats. Yet the sacrifice of isolation is worth the fish populations and the beautiful countryside.

Missouri River Map and Fishing Access Sites

Map of fishing access spots on the Missouri River in Montana

Get Directions to the Fishing Access Points shown above with the DIY Fly Fishing Map

River access is not a challenge from the Holter Dam to the city of Cascade. Numerous public access sites can be found coupled with understanding landowners. Please be mindful of the landowners requests, as this is a privilege, not a right for us. Wade fishing is aplenty, as are the options for floating the river.

Headhunters Fly Shop publishes an excellent Missouri River fishing map showing the location of MT FWS Fishing Access Sites, boat ramps and wade fishing areas.

missouri river fishing map

You can get directions to fishing access sites and boat ramps using with the DIY Fly Fishing Web App.

When is the Best Time to Fly Fish on the Missouri River

Amazingly fertile, with prolific hatches of mayflies, caddis, and midges, the Missouri River fishes well year-round. You’ll see fish rising just about every day of the year.

June through August is the prime time of year for fly fishing this portion of the Missouri River. Make no mistake, you will be catching some trout. During the summer, caddis and mayfly hatches are so prolific that it looks as though there is a mini blizzard over the river.

The MO also fishes fantastically in the shoulder seasons of Spring and Fall with Baetis and midges for dries and big, ugly streamers! 

Gear and Fly Selection for the Missouri River

The Missouri River is a heavily fished waterway, especially from June through August. While the populations of fish are phenomenal, this does not mean that they are easy to catch. Lighter tackle will serve you well.

Due to the heavy pressure found on this waterway, a precise and delicate approach will be necessary to attract the larger trout. These finicky trout will respond better to lighter tackle and drag free floats.

Sizes 16-22 of the PMD Cripple, Sparkle Dun, and Parachute PMD have seen great results for topwater action during the PMD hatch for instance. If nymphs are your favorite, sizes 16-20 of the Pheasant Tail Nymph and Hare’s Ear Nymph satisfy the curiosity of the trout.

Spey fishing on the Missouri River with Headhunters Fly Shop

The team at Headhunters refers to the time from November to April as “swing season”. Why? Because it’s fun and the Missouri River is on one of the best “swinging” trout rivers in the world. It’s also an effective – often deadly – method during the fall, winter and spring months on the Missouri River.

Missouri River Fishing Reports

A number of local fly shops, guides and on-line retailers publish Missouri River fly fishing reports.  A few to check out are listed below.

River Flow and Current Conditions

Missouri River USGS Flow, Gauge Height and Temperature

  • Temperature: 50.36 ° F
  • Streamflow: 6000 ft³/s
  • Gage height: 3.48 ft
Temperature GraphStreamflow GraphGage height Graph

Planning a Trip to Fish the Missouri River

Helena, Montana has a regional airport, which you might be able to get a connecting flight into. Chances are, you will want to fly into Billings Logan International Airport and then take the 3 1/2 hour scenic drive into your fly fishing destination.

I always suggest to the anglers who make the trip to this beautiful part of the country to get a rental and take in all that Montana has to offer. The drive from Billings into Helena, which is where I would recommend you stay, is a simple one.

Leaving the airport you will spend 43 miles on MT-3, 70 miles on MT-3/US-12, 29 miles on MT-294, 8 miles on US-89, and then a short hour’s drive on US-12 which takes you directly into Helena.

Where to stay is not an issue while planning this fishing trip of a lifetime. The city of Helena, conveniently located 45 miles to the south of Holter Dam and right off of I-15, holds numerous hotels and restaurants.

Most of all, cherish the memories that will be made as they last a lifetime. Not many anglers are so fortunate as to have fished these types of waters in parts of the country such as this.

Looking for more places to fish in Montana? Check out our DIY Guide to the Best Fly Fishing in Montana