An Overview of Idaho's Rivers and Lakes

Largest and Most Famous Rivers, Lakes, Reservoirs, and Streams

Idaho’s hydrology is anchored by the Snake River, which arcs across the Snake River Plain and carves Hells Canyon on the Oregon border. Major tributaries include the Salmon (“River of No Return”), the Clearwater (with the Lochsa and Selway), the Boise, Payette, Weiser, Owyhee, Bruneau, Raft, Portneuf, Henrys Fork, Teton, Big Wood, Little Wood, Big Lost, Little Lost, and northern rivers such as the St. Joe, Coeur d’Alene, Priest, Moyie, and Kootenai. Signature lakes and reservoirs include Lake Pend Oreille, Coeur d’Alene Lake, Priest Lake, Lake Cascade, Dworshak Reservoir, American Falls Reservoir, Palisades Reservoir, Lucky Peak, Arrowrock, Anderson Ranch, the Hells Canyon–Oxbow–Brownlee complex, Island Park, Henrys Lake, and alpine gems like Redfish and Alturas.

Water Sources for Rivers and Lakes

Most flow is snowmelt‑driven from the Rocky Mountains and ranges such as the Sawtooths, Bitterroots, and Tetons. The Eastern Snake River Plain Aquifer and large spring complexes (e.g., Thousand Springs) contribute substantial baseflow to the middle Snake.

Types of Rivers

Idaho features:

Mountain whitewater (e.g., Lochsa, Selway, Payette forks, Middle Fork Salmon).
Spring‑fed reaches along the Snake and tributaries sustained by aquifer outflow.
Arid‑basin tributaries (Owyhee, Bruneau, Jarbidge) with deep canyons and flashy hydrographs.

Types of Lakes

Large natural lakes dominate the north (Pend Oreille, Coeur d’Alene, Priest), while major reservoirs provide storage and hydropower (Dworshak, American Falls, Palisades, Lucky Peak, Anderson Ranch, Cascade, Brownlee/Oxbow/Hells Canyon). High‑elevation glacial/alpine lakes dot the Sawtooth and White Cloud ranges.

River Directions

Principal drainage is to the Columbia River via the Snake. Northern rivers flow to Lake Pend Oreille (then the Pend Oreille River), or directly to the Snake (e.g., Clearwater), while southeast basins (e.g., Bear River) exit the state toward the Great Basin.

Rivers, Navigation & Dams

Hydropower and irrigation dominate management: the Hells Canyon Complex (Brownlee–Oxbow–Hells Canyon) on the Snake; American Falls, Minidoka (Lake Walcott), Palisades; and on tributaries Dworshak (North Fork Clearwater), Anderson Ranch & Arrowrock (Boise), Lucky Peak, Black Canyon & Cabin Creek (Payette), Cascade, Deadwood. Navigation is limited; recreation rules.

Recreation on Rivers and Lakes

World‑class whitewater (Middle Fork Salmon, Selway, Payette), trout fishing (Henrys Fork, Silver Creek, South Fork Boise), boating on Pend Oreille, Coeur d’Alene, Priest, Cascade, and flatwater canyons on the Snake.

Flooding and Building Issues

Spring rain‑on‑snow and rapid warming can drive floods, particularly on the Boise, Payette, and northern rivers; steep burn scars amplify debris and sediment pulses.

Support for Agriculture

Extensive canal systems on the Snake River Plain (e.g., North Side, Milner–Gooding, Twin Falls, New York Canal) distribute storage from American Falls, Lake Walcott, Jackson Lake/Palisades, and Lucky Peak/Arrowrock/Anderson Ranch to farms and cities.

Water‑Quality Issues

Concerns include nutrients and late‑season warm temperatures in impoundments, metals legacy in parts of the Coeur d’Alene Basin, and aquatic invasive species management statewide.

Restoration & Flow Management

Flow coordination among Snake reservoirs and tributary projects supports fish, recreation, and irrigation; ongoing habitat restoration targets salmon/steelhead in the Salmon and Clearwater basins.

Idaho Rivers, Lakes, Streams and Water Features

Rivers Snake River — Tailwater/regulated mainstem Salmon River — Freestone (Wild & Scenic) Middle Fork Salmon River — Freestone South Fork Salmon River — Freestone Little Salmon River — Freestone Clearwater River — Freestone (mainstem; NF is tailwater) Lochsa River — Freestone Selway River — Freestone North Fork Clearwater River — Tailwater (below Dworshak) Boise River — Tailwater (below Lucky Peak) North Fork Boise River — Freestone Middle Fork Boise River — Freestone South Fork Boise River — Tailwater (below Anderson Ranch) Payette River — Regulated mainstem North Fork Payette River — Tailwater (below Cascade) South Fork Payette River — Freestone Middle Fork Payette River — Freestone Weiser River — Freestone Owyhee River — Freestone (ID reach) Bruneau River — Freestone Jarbidge River — Freestone Raft River — Intermittent/freestone Portneuf River — Spring-influenced freestone (regulated) Blackfoot River — Tailwater (below Blackfoot Dam) Henrys Fork (North Fork Snake) — Spring-fed tailwater Fall River — Freestone Teton River — Spring creek (upper; spring-influenced) Big Wood River — Freestone (upper; regulated below Magic) Little Wood River — Tailwater (below Little Wood Reservoir) Big Lost River — Spring-fed tailwater (below Mackay) Little Lost River — Spring-fed freestone Camas Creek — Intermittent/freestone Salmon Falls Creek — Tailwater (below S.F. Creek Dam) Bear River (SE Idaho) — Tailwater/regulated Malad River — Spring creek Kootenai River — Tailwater (below Libby) Moyie River — Freestone St. Joe River — Freestone St. Maries River — Freestone Coeur d’Alene River — Freestone Spokane River — Tailwater/regulated Clark Fork River (ID reach) — Tailwater (below Cabinet Gorge) Palouse River (headwaters) — Freestone (seasonal) Potlatch River — Freestone Priest River — Freestone (lake-outlet) Lakes & Reservoirs Lake Pend Oreille — Natural lake (level regulated) Coeur d’Alene Lake — Natural lake (regulated) Priest Lake — Natural lake (regulated) Lake Cascade — Reservoir Dworshak Reservoir — Reservoir American Falls Reservoir — Reservoir Palisades Reservoir — Reservoir Island Park Reservoir — Reservoir Henrys Lake — Natural lake (regulated) Lucky Peak Lake — Reservoir Arrowrock Reservoir — Reservoir Anderson Ranch Reservoir — Reservoir Blackfoot Reservoir — Reservoir Lake Walcott (Minidoka) — Reservoir Ririe Reservoir — Reservoir Magic Reservoir — Reservoir Little Wood Reservoir — Reservoir Mackay Reservoir — Reservoir Salmon Falls Creek Reservoir — Reservoir Brownlee Reservoir — Reservoir Oxbow Reservoir — Reservoir Hells Canyon Reservoir — Reservoir Deadwood Reservoir — Reservoir Lake Lowell (Deer Flat) — Reservoir Payette Lake — Natural lake Warm Lake — Natural lake Redfish Lake — Natural lake Alturas Lake — Natural lake Stanley Lake — Natural lake Pettit Lake — Natural lake Yellow Belly Lake — Natural lake Spirit Lake — Natural lake Hayden Lake — Natural lake Twin Lakes — Natural lakes Hauser Lake — Natural lake Fernan Lake — Natural lake Priest Lake Upper — Natural lake Priest Lake Lower — Natural lake C.J. Strike Reservoir — Reservoir Canals & Projects American Falls Canal System — Irrigation canal system North Side Canal — Irrigation canal Milner–Gooding Canal — Irrigation canal Twin Falls Canal — Irrigation canal New York Canal (Boise Project) — Irrigation canal