Blue River Fly Fishing

blue river


Located approximately 60 miles west of Denver, Colorado, the Blue River is a quality freestone and tail-water fishery consisting of enormous rainbow trout below Dillon Reservoir.

The Blue also has a good population of brown and some brook trout. Mysis shrimp and prolific hatches provide a superb food source for the trout in this “Gold Medal” fishery. Be sure to check the special regulations before heading out.

The Blue River is another one of Colorado’s exclusive Gold Medal waters. Only 168 miles of Colorado’s 9,000 miles of trout streams carry this elite designation. 2002 produced fish up to 33″ from Elktrout’s 3 miles of exclusive water on the Blue.

Heavy rainbows, browns, cutts and cuttbows live in the long runs, pools and pocket water. Generally wide open, the Blue is very accessible and relatively easy to wade.

Because the Blue is a tailwater, fishing can be very good early in the year. Stonefly nymphs produce large rainbows and browns up to 28″ and more. These are big, healthy, strong river fish so be prepared for a fight!

You can expect to fish 3x tippet here on nymphs, 4x and 5x when the caddis hatches get going in May and June. There’s a good Green Drake hatch on the Blue in July, often overlapping with Red Quills, Slate-Winged Mahoganys and caddis. With this much surface action, the rainbows and browns are looking up and provide one of the best opportunities for a large river fish on dries.

Dillon Reservoir

Above Dillon Reservoir the river is a freestone fishery while below it is a tail-water. The Blue averages from 80-100 feet across, flowing through the Gore Mountains on its course to where it meets the Colorado River near Kremmling. The rivers entire length is paralleled by Route 9, which provides ample access to this fine fishery.


Flowing north as a small stream, the Blue River passes Breckenridge and the famous ski slopes associated with this town, on its way to Dillon Reservoir. This is high terrain at over 8,000 feet above sea level. With this in mind you can imagine the scenery found along certain stretches of the river. In this upper stretch, which is approximately 10 miles in length, the river boosts an excellent population of trout averaging 12-14 inches with some in the 16-20 inch range. Deep runs, pools, and classic riffles characterize this section along with consitant, quality hatches.


Below Dillon Reservoir the river flows through urban Silverthorne on its way to Green Mountain Reservoir which is located approximately 20 miles downstream. Just below the dam Interstate 70 crosses the river. This section of the Blue is where you will find some of the largest trout in the state, competing with the trout of the Fryingpan and South Platte Rivers, which also reach immense size. Rainbows here average 16-17 inches with fish 4-6 pounds not uncommon. In fact, rainbows to 10 plus pounds exist below Dillon Reservoir. The large trout of the Blue River are mainly concentrated in the first couple of miles below Dillon Dam, where special regulations have made this area catch-and-release. These trout gorge themselves on the thousands upon thousands of mysis shrimp that spill into the river from the reservoir.

Downstream from the catch-and-release area the size of the trout diminishes although there are still hefty trout to be found to 18 inches and sometimes larger. The hatches below the catch-and-release area increase in intensity. Green Drakes hatch with enthusiasm during the summer months of July and August while pale morning duns, red quills, terrestrials, stoneflies and caddis all fill their share of the action. During the spring and fall, baetis (blue-wing olives) and midges bring trout to the surface. Access is abundant along Route 9 all the way to Green Mountain Reservoir.

Deep runs, classic riffles, and beautiful pools all characterize the river from Dillon Reservoir to Green Mountain Reservoir. Boulders, bends and depressions in the river bottom account for the variety of seams and excellent holding habitat for the trout. Quality angling can be found all the way to where the Blue meets the Colorado River below Green Mountain Reservoir.

Overall, the Blue River is a fine fishery. Large trout, quality hatches and beautiful water are all here. If you’re planning a trip or going to be in the Denver vicinity, consider fishing the Blue River.

Blue River Hatch Chart

InsectSizeBegin DateEnd DateBest Time
Streamers2-10April 1May 30morning and afternoon
Mysis Shrimp14-18April 1November 30all day
Midge16-24April 1November 30all day
Baetis18-22April 1May 15morning and afternoon
Golden Stone6-10June 1July 30afternoon and evening
Red Quill14-18June 15August 30afternoon and evening
Caddis10-20June 15September 15afternoon and evening
Terrestrials8-20July 1September 15afternoon and evening
PMD14-22July 1August 30morning and afternoon
Green Drake10-12July 1August 15morning and afternoon
Baetis18-22September 1October 15morning and afternoon
Streamers2-10September 15November 30morning and afternoon
Blue River Map (National Geographic Fishing & River Map Guide, 2310)
  • National Geographic Maps (Author)
  • English (Publication Language)
  • 40 Pages - 01/01/2023 (Publication Date) - National Geographic Maps (Publisher)
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