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South Dakotatroutrainbow troutbrown troutbrook troutBlack HillsGreat PlainsSpearfish CanyonPactolaMcNenny hatchery

Trout Species of South Dakota

8 min read

South Dakota’s trout fishery is concentrated in the Black Hills — an isolated forested cold-water island in the middle of the Great Plains. None of the three classic North American trout species are native to South Dakota. The state holds three introduced species: stocked and holdover Rainbow Trout, wild and stocked Brown Trout (the trophy class in Spearfish Canyon), and Brook Trout in the coldest, highest-elevation headwater refuges. Native species in SD are warmwater — walleye, sauger, smallmouth bass on the Missouri River system — but every trout you catch in the Black Hills is here because SDGFP and historic hatchery work put it here.

Why the Black Hills Hold Trout at All

The Black Hills are a 2,000-mile geological anomaly — an ancient uplifted dome of Precambrian rock rising 4,000 feet above the surrounding plains. Higher elevation means cooler air, more precipitation, and forested watersheds with cold spring-fed streams. Limestone formations within the dome feed alkaline groundwater into Spearfish Creek, Rapid Creek, and Castle Creek. The result is a fishery that has more in common with the Front Range of Colorado or the Bighorns of Wyoming than with anywhere else in the Dakotas.

  • Spring-fed and dam-regulated flows — Pactola Reservoir on Rapid Creek and Deerfield Reservoir on Castle Creek both create tailwater fisheries with stable cold-water temperatures.
  • Limestone canyon microclimate — Spearfish Canyon’s 1,000-foot walls keep water consistently cooler than surrounding plains.
  • Heavy SDGFP stocking — the Black Hills are one of the most heavily stocked regions per stream-mile in the country. Hatchery rainbows are common in every Black Hills stream; wild reproduction is dominated by brown trout.

Rainbow Trout — The Stocking Backbone

Non-native (introduced) — Stocked across every Black Hills stream

The Rainbow Trout (Oncorhynchus mykiss) is the most common trout in the Black Hills by sheer numbers — SDGFP’s McNenny State Fish Hatchery near Spearfish stocks every accessible trout stream in the Hills, with peak stocking on Rapid Creek through Rapid City and the Pactola tailwater. Holdover rainbows are common in the tailwaters and in the deeper pools of Spearfish Canyon, with some wild reproduction documented in cold spring-fed sections.

ID at a glance

SpottingHeavy black spotting on a silvery body, spots covering the back, sides, and tail — diagnostic for rainbows.
StripePink-to-red lateral stripe running along the flank, brightest on mature spawning fish.
TailHeavily spotted, slightly forked.
Typical size9–14 inches across most stocked Black Hills water; holdover and stream-grown rainbows 16–18 inches in the Pactola tailwater and Spearfish Canyon pools.

Where to find them

Rainbows are heavily stocked across every Black Hills trout stream — Spearfish Creek, both Rapid Creek sections, Whitewood Creek, Spring Creek near Custer, and Castle Creek. Highest densities in the urban Rapid City reach right after spring and fall stocking events.

Brown Trout — The Trophy Class

Non-native (introduced) — Wild and stocked across Black Hills streams; trophy class in Spearfish Canyon

The Brown Trout (Salmo trutta) is the trophy fish of the Black Hills. Browns tolerate warmer water than rainbows and brookies, hold over in tailwaters and canyon pools for years, and spawn naturally in many Black Hills streams. Spearfish Canyon’s big browns are the iconic Black Hills trophy target — 18-to-22-inch fish hold under the canyon walls and feed on baitfish and large terrestrials.

ID at a glance

SpottingBlack and red spots on the back and flanks, often with pale halos around the spots — diagnostic for brown trout.
BodyButtery yellow-brown to olive-bronze, deepening to bronze on large mature fish.
TailSquare (no fork) and largely unspotted — distinguishes browns from rainbows.
Typical size10–14 inches on most water; trophy class 18–22+ inches in Spearfish Canyon pools, Pactola tailwater deep runs, and Castle Creek.

Where to find them

Brown trout hold across every Black Hills trout stream, with the trophy concentration in Spearfish Canyon. Pre-spawn fall browns become aggressive on streamers in October and November — respect any visible redds during the spawn.

Brook Trout — Cold-Water Headwater Holdouts

Non-native (introduced) — Cold headwater refuges of Spearfish and Spring Creek

The Brook Trout (Salvelinus fontinalis) is the least common of the three Black Hills trout species. Brookies require the coldest, cleanest water of any North American trout and persist in scattered headwater reaches of Spearfish Creek and Spring Creek near Custer. Like the brown and the rainbow, the Black Hills brook trout is introduced — there are no native trout species in South Dakota.

ID at a glance

VermiculationsWorm-like wavy markings on the back and dorsal fin — unmistakable and diagnostic.
SpottingRed spots with blue halos along the flanks (the only North American trout with blue halos).
FinsWhite leading edges on the lower fins (pectoral, pelvic, anal) followed by a black stripe — diagnostic.
Typical size6–10 inches in Black Hills headwater refuges; small-stream brookies rarely exceed 12 inches.

Where to find them

Look for brookies in the coldest, smallest, most-shaded headwater stretches of Spearfish Creek and Spring Creek. Cold pocket water above the main canyon and dam-regulated reaches.

Quick Species Reference

SpeciesStatusField tellWhere
Rainbow TroutNon-native (introduced)Heavy black spotting on silvery body; pink-red lateral stripe; spotted tailEvery Black Hills trout stream — Spearfish, both Rapid Creek sections, Spring, Whitewood, Castle
Brown TroutNon-native (introduced)Halo spots (black and red with pale halos); square unspotted tail; buttery bodyBlack Hills wide; trophy class in Spearfish Canyon and Pactola tailwater pools
Brook TroutNon-native (introduced)Worm-like vermiculations on back; red spots with blue halos; white-edged orange finsCold headwater refuges of Spearfish Creek and Spring Creek

Other Cold-Water Notes

Cutthroat trout are not present in the Black Hills. The Missouri River system across central and eastern South Dakota holds warmwater species (walleye, sauger, smallmouth bass, channel catfish, paddlefish in some reaches) but no trout fishery — every South Dakota trout stream is a Black Hills stream. The Black Hills sit just east of the historical Wyoming cutthroat range and well outside the native distribution of any cutthroat subspecies.