Brown to olive brown on back. Inky black spots, usually well defined, on back. Dark spotting on legs. Few or no black flecks between spots. Lower abdomen and underside of rear legs yellow, orange-yellow, or yellowish tan. Groin usually bright yellow with dark mottling. Lower sides yellowish or cream. Dorsolateral folds. Male has darkened and enlarged thumb base (Stebbins 1985). Males measure 50-60 mm in snout-vent length, females, 50-75 mm (Ronald and Dumas 1971).

Range overlaps slightly with ranges of Rana pretiosa (Spotted frog) and R. Aurora (Red-legged frog). R. pretiosa has a more conspicuous light-colored upper jaw stripe and nostrils that are set closer together an higher on the snout than R. cascadae. R. Aurora usually has red mottling on its groin and generally has smoother skin than R. cascadae (Stebbins 1985)..
 
The Cascades frog is rather non-mobile in its behavior, often allowing one to inspect it closely (Stebbins 1985).

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