Best Fly Fishing Rivers – Highest Trout Per Mile

How would you feel walking down a riverbank fishing path, if you knew the river held 7-8, in some cases even 10+ fish for every step you took? Here we countdown some of the best fly fishing trout streams – with so many trout you could almost trip over them.

What’s in the number, anyways?

Did we get your attention in the intro?  Of course, it’s still up to you to catch them!  Here’s how we know many per mile at these incredible fly fishing destinations.  Our hats (and vests) are off to the women and men at state and federal fisheries agencies.  They are often supported by non-profits and universities, who diligently study and monitor fisheries to ensure they stay healthy.  Fish per mile represents one key measure of best trout fishing productivity – among many important indicators.

Stream quality studies take scientists a lot of time and expense to conduct, so are usually done every several years at most.  For this reason, counts are rarely done every year, and sometimes even a decade or more apart.  One of my first summer jobs in college was helping with fish surveys, and I have many fond memories of the summer.   For example, “saving” one day’s work casting over our lunch break which landed the only smallmouth bass seen that day.

Related Article: The Best Fly Rods For Trout

How do these fish studies help?

Once trends are established, fisheries scientists work hard to analyze the factors that change fish populations.  They do this by species, to identify management strategies to maintain a healthy population.  Catch number and size limits, catch & release stretches, and stocking strategies are informed by population studies.  In fact, they put some really involved science and math into these studies.

So, we’ll point you to some of the best trout fishing in the US with this information.  But, it won’t necessarily help you with how to catch trout in a river – that’s another topic altogether.  Of course, river trout fishing depends on many other factors.  Trout need the right flow levels, temperature, insect populations, invasive species, fishing pressure, and water quality.  Trout are an indicator species that do well when river conditions are pristine.

Speaking of which, here we present some of the best trout streams in America, Top 5 as we know them so far in countdown order.  Studies take time to find and review, so we don’t claim to have every one listed.  Perhaps you know of one with more fish than these (based on a study not a fisherman’s tale!).  If so please let us know right away on our Contact page so we can update this post!

5. Madison River, Montana & Wyoming

Many of the best places to fly fish in Montana and Wyoming, believe it or not, have fish counts in the 2000-4000 range.  That may not sound like a lot of river trout compared to some places.  Yet these rivers sport wild populations that don’t hesitate to bite.  The Madison is perhaps the most famous of them all, with prolific hatches and great fly fishing.  Flowing out of its headwaters in Yellowstone National Park, the Madison pushes 6,000 trout per mile.  Needless to say, that creates some awesome fishing from top of the watershed to bottom in both states.  It is so productive and famous, not to mention harbors plenty of big rainbow and brown trout, that management strategies address fishing pressure more so than some of its less famous cousin rivers nearby, keeping this river in top notch shape.

4. Crooked River, Oregon

A tributary to the more famous Deschutes, but with more fish per mile, the Crooked River is a terrific tailwater.   It boasts strong numbers of native “Redside” or “Redband” rainbow trout (named for a deeper red stripe) and mountain whitefish.  Populations typically range from 4,000 to 7,000 fish per mile.  The count can hit more than 8,000 trout per mile, and less than 1,000 in years affected by extreme high water or low snow-pack events.

Fortunately, the Crooked flows are moderated by upstream Arthur Bowman dam & lake operations.  The river usually holds a huge number of fish per mile, and has about 8 miles of easily accessed river.  You may not catch your largest rainbow trout in this river, as the average size is lower than many, but you can be certain it is some of the best stream fishing for trout.  Thanks to the Oregon Department of Fish and Wildlife, and US Bureau of Reclamation for managing this river so well under highly variable natural conditions.

3. Upper Kenai River, Alaska

The Kenai is inspirational just by mention.  While it might be best known for its prolific runs of sockeye salmon and giant Kings (not to mention the world record King of 97 pounds was taken here), most fly fishing takes place on the upper Kenai.  The 17-mile stretch from Kenai Lake to Skilak Lake is home to not only dense rainbows, but also Dolly Varden.

Not counting the huge salmon runs (like over 1,000,000 sockeye alone in some years), the resident rainbow population is about 6,000 per mile.  Add on top of that Dolly Varden and other resident fish and you’re pushing 10,000 fish per mile.  Not only that, they are large rainbow trout on average, and the wild fish fight like crazy.  My favorite picture ever is the contented look of my daughter landing her first large rainbow completely by herself after a battle. Those bows know how to use the current and acrobatics to break you off.

Related Article: How To Catch Trout In The Spring

2. San Juan River, New Mexico, Colorado, and Utah

The San Juan is no doubt one of the best trout streams in the country, with nearly 15,000 fish per mile.  I can attest  – after getting nearly skunked on a backpacking trip on another famous river in August 2017, typically the slowest month of the year, my brother and I spent one morning on the San Juan river.  Needless to say, we pulled out more fish than nearly a week on the other river.  Primarily rainbows, but don’t overlook the large browns here as well.  This river crosses three states in rapid succession.  So, you should double-check know the rules for fishing and have a license for the state you are in.

1. Green River, Utah

The tailwaters flowing out of the Flaming Gorge Reservoir hold, can you believe it, over 20,000 fish per mile!  The Utah Division of Wildlife Resources estimates these dense populations in at least in the upper stretches of the tailwater.  We’ll cover fish sizes in another article, but suffice it to say you can catch plenty of big rainbows and monster brown trout.

Related Article: The Best Trout Flies

Readers often know best – if you know of a river with more fish than these (based on a study not a fisherman’s tale!), please let us know right away on our Contact page so we can update this post!  For articles on how to fish for trout in a stream or river, visit our next article below or check out all of our articles by visiting our home page.  Now that we’ve pointed you to where to fish, be sure to hone your skills in how to find and catch trout on big rivers and streams.


WATCH: Green Envy – Fly Fishing Utah’s Green River