Colorado has five tailwaters that grow trout on Mysis shrimp, scuds and stable flows, and five freestone rivers that run the full hatch calendar from Salmonflies to hoppers. The state uses "Gold Medal" rather than Blue Ribbon, awarded by Colorado Parks and Wildlife on measured trout biomass and the density of fish over fourteen inches. Every river below is on this site with its own conditions page; the Front Range, Roaring Fork Valley, Gunnison country and the upper Colorado are all represented.
Gold Medal tailwaters
Frying Pan River, Colorado
The Frying Pan below Ruedi Reservoir is the Colorado tailwater everyone has heard of, and the reason is Mysis shrimp washing through the dam into the mouths of rainbows that grow unusually deep-bodied. The Toilet Bowl and Seven Castles pools near the outlet hold the largest fish. It is a midge and Blue-Winged Olive river from October through April, with a Red Quill in spring and fall, PMDs from June through August and Tricos in July and August. Basalt, at the bottom, has more access and fewer people.
Taylor River, Colorado
Below Taylor Park Reservoir the Taylor is the best brown trout tailwater in the state. The dam outlet is the trophy water, technical and small; Lottis Creek campground is the accessible middle stretch that fills on summer weekends; Almont is where the Taylor meets the East River and becomes the Gunnison. Fish it with 5X or 6X and a good drift rather than a big fly.
Blue River, Colorado
Two miles of Gold Medal water below Dillon Reservoir run past the Silverthorne outlet stores, with a walk-wade trail and a river parkway through town. The browns are heavily pressured and selective. Winter is the season the locals like: midges on mild days with the ski crowd on the mountain, then Blue-Winged Olives in fall. The canyon along CO-9 toward Kremmling is less crowded.
Gunnison River, Colorado
Gold Medal from Almont down through the Black Canyon and the Gunnison Gorge. Almont has easy wade and float access and good PMD, caddis and Golden Stone hatches in summer. The Black Canyon is a serious undertaking, with six designated routes into the gorge and a hard climb out, and the browns down there are the reason people do it. The Gorge below the park is raft water managed by the BLM.
South Platte River, Colorado
Cheesman Canyon and Deckers are the Front Range's Gold Medal water within reach of Denver. The canyon is a two-and-a-half-mile trail hike to selective wild browns; Deckers has paved River Road access and more rainbows. Midges and Blue-Winged Olives carry the fishing from October through April, PMDs and caddis fill early summer, and Tricos come in July and August. Weekdays are the answer to the weekend crowd at Deckers.
Freestones of the Arkansas, Roaring Fork and Eagle
Arkansas River, Colorado
The Arkansas around Salida is the most accessible Gold Medal water in the state: walk-wade from the River Park to Stone Bridge, US-50 pull-offs from Howard to Coaldale, and the float through Brown's Canyon National Monument from Ruby Mountain to Hecla Junction. Wild browns dominate. Salmonflies in June, Golden Stones through July, caddis from May to August and Tricos in July and August cover the calendar, and midges bring fish up in January.
Roaring Fork River, Colorado
The Roaring Fork is a mountain freestone above Basalt and a big brown trout river below it, once the Frying Pan's cold water joins in. Aspen has pull-offs along CO-82 and Castle Creek Road for summer dry fly fishing; the Blue Ribbon lower river from Basalt to Glenwood Springs is float water with the largest fish. Salmonflies in June and PMDs through August fish best up top; October streamers for pre-spawn browns are the lower river's season.
Eagle River, Colorado
The Eagle runs from Minturn below Vail through Wolcott and Eagle to the Colorado confluence at Gypsum, with I-70 frontage roads reaching much of it. The canyon below Minturn is the prime water, walked downstream from the US-24 bridge. Browns dominate and feed on Salmonflies in June, caddis from May through July and Blue-Winged Olives in fall. Gypsum in October holds large pre-spawn browns.
The upper Colorado and the Poudre
Colorado River, Colorado
The upper Colorado through Grand County is Blue Ribbon quality from Pumphouse Recreation Area down to State Bridge, about sixteen river miles that most people float. Walk-wade water surrounds both access points. Rainbows dominate up high on PMDs and caddis in summer, browns own the lower canyon and take streamers hard in October, and Gore Canyon above Pumphouse is a hike-in that almost nobody bothers with.
Cache La Poudre River, Colorado
The Poudre is Colorado's only Wild and Scenic river, and CO-14 gives continuous access from Fort Collins through the canyon. The lower canyon is closest and busiest; Rustic to Mishawaka balances access and solitude with campgrounds and good caddis and PMD water; the upper canyon above Poudre Park is smaller water with native Colorado River cutthroat alongside rainbows and browns. Salmonflies in June, Golden Stones through July, hoppers in July and August.
Timing a Colorado season
The tailwaters fish year-round and are the spring answer while the freestones are in runoff, which typically runs from May into mid or late June. The Frying Pan, Blue and South Platte are legitimately good in January on midges. The freestones come alive with the Salmonflies in June and stay strong through hoppers in August; October is streamer month for browns on the Roaring Fork, Eagle, Colorado and Arkansas. Gold Medal stretches usually carry special regulations, including flies-and-lures-only and catch-and-release rules, and they are section-specific; check Colorado Parks and Wildlife for the water you plan to fish.