Montana Fly Fishing 5 min read

DIY Guide to Fly Fishing the Clark Canyon Reservoir in Montana

Ken Sperry

Posted by Ken Sperry

February 20, 2024

Clark Canyon Reservoir in Montana

While a lot of anglers head out to Montana’s famous rivers to fly fish, larger bodies of water such as the Clark Canyon Reservoir can provide fantastic fishing for large rainbow and brown trout, as well.

If you are planning a fly fishing trip to Montana, consider this beautiful location along the Lewis & Clark Trail. Although it may not be the first fly fishing destination people consider, it has a lot to offer.

About Clark Canyon Reservoir

Fly Fishing the Clark Canyon Reservoir in Montana early in the season after ice out can yield some beautiful rainbow trout.

Montana is a large state with a lot of lakes, rivers, and creeks. However, you shouldn’t discount this large reservoir that spans almost 5,000 acres and is the source of the famed Beaverhead River. It has a lot to offer anglers and all lovers of the outdoors.

There are many types of fish including those that respond well to flies. You can spend one day or several days at the reservoir. 

Consider using one of the campgrounds at the reservoir as your base and then explore the area. You will also find that Clark Canyon Reservoir is near a range of streams, too, which are also promising for anglers.

What Is It Like at Clark Canyon Reservoir in Montana?

You will find 17 miles of shoreline at the reservoir, much of which can be used for fly fishing. However, if you want to get out on the water, there are concrete boat ramps near the main entrance and at other locations.

The reservoir has free campgrounds, where you can stay, as well as places to have a picnic.

It’s important for anglers to keep in mind that even though fly fishing is possible on the lake, this is also a recreational location that can get busy with pleasure boaters in the summer.

Type of Fish in Clark Canyon Reservoir in Montana

The lake is home to many species of fish. Fly anglers will find some great rainbow and brown trout, along with mountain whitefish. Some of the other types of fish found in the waters include common carp, long-nosed suckers, burbot, and white suckers.

The size of the fish can vary substantially, but you shouldn’t have trouble hooking fish that are at least 12 to 16 inches long. You may even find some that are much larger.

What to Expect at Clark Canyon Reservoir in Montana?

You will find campgrounds at the reservoir, but there’s no marina or boat rental at the reservoir. If you want to rent a boat, you will have to do it in Dillon or nearby. The reservoir does have boat launch ramps.

You also won’t find a convenient store or bait and tackle shops at the reservoir. Again, you will want to bring what you need with you.

Clark Canyon River Fishing Map

Map of Clark Canyon Reservoir in Montana

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

Best Places to Fish on the Clark Canyon Reservoir

Although you may be able to fish along the shore in some spots on Clark Canyon Reservoir, you may find that it will be easier to reach certain areas in a boat.

When fishing for trout and hoping to find a good spot on or along the reservoir, consider what trout like. They tend to like drop-offs and dark spots in the water, undercut banks, low-hanging vegetation, and cold water.

Whether walking the shoreline or taking a boat, you can find locations across the reservoir that could work well for your fly fishing needs. Go to areas that aren’t being frequented and be patient.

If you are going to use a boat, a kayak, canoe, pontoon, float tube or drift boat works well when there is only light wind. A motorboat would be a better options during windier conditions.

There are several boat launch ramps and landings:

  • Beaverhead Boat Launch Ramp – Located along the northeastern part of the lake just off Clark Canyon Dam Road.
  • Horse Prairie Boat Launch Ramp – Located in the northwestern part of the lake off of Route 324.
  • Northwest Boat Launch Ramp – Located in the northwestern area of the lake. This ramp is also located off Route 324.

Best sure to also check out the Red Rock River channel at the southern end of the reservoir. This is a productive spot that produces large fish when they make their annual spawning runs up the river from the Reservoir.

Best Time to Fish the Clark Canyon Reservoir

Spring and the beginning of summer tend to be the best times to head to Clark Canyon Reservoir. Right after ice out is usually the best and most consistent time to fish. Fly fishing southwest Montana in April can be a bit chilly, but it’s well worth it!

One of the things to note about late summer is that the reservoir can get extremely low. This is because the water is used for irrigation.

During the winter, you will find that the reservoir freezes, so fly fishing is out of the question. It is a popular place for ice fishing, though.

Best Flies for Clark Canyon Reservoir

You will find that classic stillwater wet flies, like the Sheep Creek Special and the Stayner Ducktail, streamers and nymphs all work well on the reservoir.

Woolly Buggers, leeches, damsel and dragonfly nymphs are all staples here. Of course your favorite chironomid patterns in chrome, red, olive and black will also be productive.

Top water action is not too common but hatches of Callibaetis, midges and tricos will get the trout looking up.

Here is a list of general fly pattern recommendations for the Clark Canyon Reservoir:

Dry Flies

  • Parachute Adams (#12 – 22)
  • Elk Hair Caddis (#8 – 16)
  • Callibaetis Deer Hair (#12 – 16)
  • Chernobyl Ant (#8 – 12)
  • Griffith’s Gnat (#16 – 24)


  • Pheasant Tail (#12 – 20)
  • BH Hare’s Ear (#12 – 20)
  • Tellico Nymph (#12 – 18)
  • Zebra Midge (#16 – 22)
  • WD40 (#16-20)
  • Sheep Creek Special (#8 – 12)
  • Stayner Ducktail (#8 -12)


  • BH Wooly Bugger (#2 – 6)
  • Sculpzilla (#4)

Gear Recommendations

A 9-foot 5- or 6-wt fly rod and matching fly reel with floating line is perfect for fishing nymphs under an indicator on the Clark Canyon Reservoir. A sinking or sink-tip fly line is best for stripping streamers and wet flies.

A tapered 9-foot leader, with tippet size 3X to 5X to match the flies you are throwing, is pretty standard. Longer leaders may be necessary if you are targeting rising fish.

Clark Canyon Reservoir Fishing Report

Area fly shops, guides and websites that can provide a Clark Canyon Reservoir fly fishing report and update on current conditions are listed below:

Fishing Regulations

The state of Montana requires that all people who are 12 years of age and older have a valid fishing license. There are resident and non-resident sport fishing licenses available.

You can purchase a Montana state fishing license and learn about the most current regulations through the Montana Fish, Wildlife & Parks.

Trip Planning Tips

Make sure you take along all of your appropriate gear including rods, flies, leaders, tippets, safety gear, etc. Bring along a boat too—or rent one—if you want to get out on the water rather than stick to the shoreline.

The closest town to the reservoir is Dillon. It can be reached by heading south on the I-15 for about 20 miles. You can head to the main pull-off for the reservoir, where you will find the parking, picnic tables, picnic shelters, etc.

The reservoir itself is large, and it holds 96 campsites, including RV sites, that are near the water. This can be a nice option for those who want to spend some time close to the action. Just keep in mind that it can be busy, particularly during the summer months.

However, if you would rather stay indoors, you can find some accommodations in Dillon. You could stay at the Beaverhead Lodge, Beaverhead Resort, or any number of affordable accommodations in the area that could be a nice solution.

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