Cheesman Canyon
14 Day Forecast: Look for sporadic hatches of midges and blue-wnged olives.
Effective Patterns: #20-22 Top Secret Midge, #20-22 Manhattan Midge, #20-22 Jujubaetis, #20-22 Top Secret Baetis, #20-24 Chocolate Foam Wing Emerger, #18 Micro Egg, #20-22 Red Larva, #20 Mercurry Blood Midge, #20 Flashback Mercury Black Beauty, #20 Buckskin, #20-22 Pat's Midge, #20-24 Griffith Gnat, #20 Mole Fly, #20 Mathew's Sparkle Dun, and #20 Parachute Blue-Winged Olive.
Measurements
Stream Conditions & Tips from Pat Dorsey for Fly Fishing Cheesman Canyon in Colorado
The picturesque boulder-filled Cheesman Canyon portion of the South Platte River is considered by many one of the most pristine fisheries in the world. This area, often times simply referred to, as “the Canyon” is an experience you’ll never forget. It’s the perfect scenario, magnificent beauty in combination with great fly fishing.
The South Platte River carves its way through a granite canyon lined with ponderosa pines, willows, fallen tree trunks, and various other assorted ground foliages. Boulders as big as Volkswagens Beetles create structure for the super-selective trout residing in the river. Mule Deer, Black Bear, Raccoons, Mountain Lyons, and Bald Eagles all add to the experience. Anglers can expect to catch mostly large rainbows supplemented with a few nice brown trout. The aforementioned “canyon” is as technical as they get, and if you can catch trout here, you can catch them anywhere in the world. This three-mile section is primarily a nymphing fishery requiring tiny midge and mayfly imitations with fine 5 and 6X tippets. Ideal flows for Cheesman Canyon are between 250 and 400 cfs. The regulations are flies and lures only. All fish must be returned to the water immediately.
Cheesman Canyon is one of the best tailwaters in the country. There's a common belief among "canyon regulars" that if you can catch fish on the South Platte River, you can fool fish anywhere in the world. There's no substitution for good technique in Cheesman Canyon.
Tips & Other Information:
Outflows are currently 249 cfs below Cheesman Reservoir, but they have been up and down like a yo-yo. In the past week, or so, the outflows have beeen adjusted 5 times to meet downstream demand. Cheesman Reservoir is currently at 86% capacity as of this morning. This is a bit counter intuitive, but Denver Water expects the outflows to be in the 200-250 cfs range most of the summer. The “rainbow trout spawn” is still in full swing so watch your step in the shallow riffles. If you see rainbows in shallow riffles assume they are spawning and leave them alone. The hatches have been light which is further complicating things. Anglers willing to cover a lot of water and work hard are bringing a few nice fish to hand, however. Revised 6/17/26