Upper Colorado River Basin

Parts of the seven states of Wyoming, Colorado, Utah, New Mexico, Arizona, California, and Nevada form the U.S. portion of the 243,000 square-mile Colorado River Basin. The 1922 Colorado River Compact, created by these seven states, separated the basin into an upper and lower region with Lee’s Ferry just below Glen Canyon Dam as the point of division. Wyoming, Colorado, Utah, New Mexico, and the northern portion of Arizona make up the 109,800 square-mile Upper Basin. Major tributaries of the Upper Basin include the Green, San Juan, Escalante, Gunnison, and Dolores Rivers, and the Lower Basin is fed largely by the Paria, Virgin, Little Colorado, Bill Williams, and Gila rivers (Pontius and SWCA 1997).

Map of the HUC 6 watershed sub-basins in the Upper Colorado River Basin that were used for this analysis. Click on the polygons to obtain information about listed species by taxa in each HUC 6 watershed (as of 23 January 2025). Or click here to open the map online.

The following is a table of listed species and critical habitats in the Upper Colorado River Basin. Click on the blocks below to obtain more detailed information about the listed species and critical habitats in each HUC 6 (as of 23 January 2025).

The following table is a summary of listed species and critical habitats by taxa in the Upper Colorado River Basin.

Birds

Photo credit: Gunnison Sage Grouse, Gary Kramer, USFWS

California Condor (Gymnogyps californianus) (EXPN) (proposed CH)
Eastern Black Rail (Laterallus jamaicensis spp. jamaicensis) (T)
Gunnison Sage-grouse (Centrocercus minimus) (T) (CH)
Mexican Spotted Owl (Strix occidentalis lucida) (T) (CH)
Piping Plover (Charadrius melodus) (T) (CH)
Southwestern Willow Flycatcher (Empidonas traillii extimus) (E) (CH)
Whooping Crane (Grus americana) (E) (CH)
Yellow-billed Cuckoo (Coccyzus americanus) (T) (CH)

Fishes

Photo credit: B. Gratwicke

Bonytail (Gila elegans) (E) (CH)
Colorado Pikeminnow (Ptychocheilus lucius) (E) (CH)
Greenback Cutthroat Trout (Oncorhynchus clarkii stomias) (T)
Humpback Chub (Gila cypha) (T) (CH)
Kendall Warm Springs Dace (Rhinichthys osculus thermalis) (E)
Pallid Sturgeon (Scaphirhynchus albus) (E)
Razorback Sucker (Xyrauchen texanus) (E) (CH)
Rio Grande Cutthroat Trout (Oncorhynchus clarkii virginalis) (C)
Rio Grande Silvery Minnow (Hybognathus amarus) (E) (CH)
Zuni Bluehead Sucker (Catostomus discobolus yarrowi) (E) (CH)

Mammals

Black-footed Ferret (Mustela nigripes) (EXPN) (E)
Canada Lynx (Lynx canadensis) (T) (ECOS) (CH)
Gray Wolf (Canis lupus) (EXPN) (ECOS)
Grizzly Bear (Ursus arctos horribilis) (T) (ECOS) (proposed CH - but never finalized - no overlap with any project locations)
Mexican Wolf (Canis lupus baileyi) (E) (EXPN)
New Mexico Meadow Jumping Mouse (Zapus hudsonius luteus) (E) (CH)
North American Wolverine (Gulo gulo luscus) (T)
Utah Prairie Dog (Cynomys parvidens) (T)