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Fly Fishing The Big Thompson River – Complete Guide w/ Map, Pictures, Tips & More


Article Categories: Fishing

The Big Thompson River (The Big T) begins in Rocky Mountain National Park in Forrest Canyon, through Estes Park, and all the way along Highway 34 to Loveland, CO. Pretty much every section of river is productive. Anglers can expect to catch rainbow trout, brook trout, brown trout, and Rocky Mountain National Park’s famous Greenback Cutthroat trout.

River Map
Best Places to Fish
Rules & Regulations
Current Flows


River Map

Below you will find all major points of the Big T marked. Message us if you want more added!


Best Places to Fish the Big T

There are various places to fish the Big Thompson, and all of them produce lots of fish. The best place to fish is dependent upon the style of water you want to fish, as well as your need to avoid crowds, and your ability to hike where others may not be as willing. For the purpose of this article, we will break the river down into three main sections.


Upper Big Thompson (Rocky Mountain National Park)

The hardest sections to reach of the Big T start in Forrest Canyon. To get to these headwaters is difficult, and should only be done by experienced hikers. If you are looking to avoid the fishing crowds, and a bit of a challenge, this is a great spot. Continuing further down stream, easy access to the Big T is located in Moraine Park. Here the views are spectacular, elk are plentiful, and anglers can come across many brown trout and greenback cutthroat. In this section the Big T breaks into various streams (all part of the Big T), and anglers have access via the roads heading through the park. Because this area has little cover from trees, it is important for anglers to approach the rivers cautiously, as the fish can easily see predators (and fisherman) coming.

The section of river that exits the park and heads towards Estes is not as fished due to it not being considered as productive as other areas. This area does produce fish, and has access points along roads. Be sure to avoid private property marked areas.


Lake Estes Area

The best sections in Estes is just downstream of Olympus Dam. There is a park with a worn path from anglers and walkers on both sides of the river. Here you will often be able to sight fish some larger fish. This area is very heavily trafficked by anglers and walkers, even in winter months. Access can be had by pulling off of Mall Road. There is a bridge here where you can often spot some bigger fish. Upstream of this bridge is the fishable water. Immediately downstream of the bridge is well marked private land. Please respect people’s private land and only fish above the bridge.

You also have some great views of the surrounding mountains. From the Dam and 9 miles downstream of the Dam is catch and release barbless hooks only. Fishing is year round.


The Canyon Below Lake Estes

This is where the fishing gets really fun, the canyon scenery is absolutely stunning, and the river is just a beautiful freestone stream littered with pocket water. The upper 9 mile section is catch and release barbless hook only, and has a very healthy population of native brown and rainbow trout.

This stretch of river is accessed by tons of pull-offs along highway 34. Nearly every pull-off, anglers will be able to spot fish, and have a chance to land one. Be aware of private property, and do not fish it. In cases where private property is marked across the stream, the rule is anglers cannot wade past halfway in the water (though anglers can cast all the way across). You will see anglers all over these pulloffs. Fishing is solid year round. Some areas get ice build up in winter that make it difficult or impossible to fish. Most fish are on the smaller side here being under a foot long.

Moving further downstream, the river enters Drake, where the convergence of the North Fork of the Big Thompson is. This area is less fished, but still contains lots of fish. The river runs through public land, private land, and even a park (Viestenz-Smith Park) where you will find many families enjoying lunch along the river.

Even further downstream, the river gets steeper, narrower, and the canyon walls get higher. This water is fishable, but be very aware of surroundings with canyon walls, and limited ability to quickly escape falling rocks or rising water.

For those with trouble accessing water, the Big T has a fishing pier on HWY 34 at Mile Marker 72.


River Rules & Regulations

From Olympus Dam (east end Estes Lake) to Waltonia Bridge requires a fly or lure (barbless) for catch and release fishing. The rest of the Big Thompson River below Waltonia general regulations for CO rivers.

You can also read the current rules and regulations here: https://cpw.state.co.us/Documents/RulesRegs/Brochure/fishing.pdf



The Big Thompson is open and fishable year round. Crowds subside in winter, but you will still see anglers. Areas during winter get ice covered making fishing difficult or impossible, but generally there is always water to fish. Peak snowmelt can also pose some high water problems.


Best Flies for Big Thompson

Dry fly dropper setups work very well. During summer months, hopper patterns work great.

Streamers are always a great backup plan, and nymphs work year round. Particularly copper johns, z-wing caddis’. Terrestrials and beetles do well for dry flies. Size 14-18 tends to be best for wet flies.


The Fish

Check out the Big Thompson River Fish Survey and management data here.

The Big T houses brown trout, brook trout, rainbow trout, and cutthroat trout.


Big Thompson Guides

If you are looking for a guide on the Big T, we can hook you up! Just fill out our guided fishing form, and we will connect you with the best guide for your needs.

Local Fly Shops And Guides:

St. Peter’s Fly Shop
Kirk’s Fly Shop
Front Range Anglers


Current Water Flows


Big Thompson River below Olympus Dam

Big Thompson River below Olympus Dam

Fishing On The Big Thompson River

Fishing On The Big Thompson River

The Narrows on Big Thompson Road

An area known as The Narrows along Big Thompson Road leading to the entrance of Rocky Mountain National Park near Loveland, Colorado.

Max DesMarais

Max DesMarais

Max DesMarais is the founder of hikingandfishing.com. He has a passion for the outdoors and making outdoor education and adventure more accessible. Max is a published author for various outdoor adventure, travel, and marketing websites. He is an experienced hiker, backpacker, fly fisherman, backcountry skier, trail runner, and spends his free time in the outdoors. These adventures allow him to test gear, learn new skills, and experience new places so that he can educate others. Max grew up hiking all around New Hampshire and New England. He became obsessed with the New Hampshire mountains, and the NH 48, where he guided hikes and trail runs in the White Mountains. Since moving out west, Max has continued climbed all of the Colorado 14ers, is always testing gear, learning skills, gaining experience, and building his endurance for outdoor sports. You can read more about his experience here: hikingandfishing/about