A large, heavy, terrestrial salamander. Gilled adults are found in some populations. Transformed adults reach sizes of 17 - 30.5 cm total length and larval adults may reach 35 cm (Stebbins 1985; Petranka 1998). In transformed adults, the dorsal color is reddish brown overlain with copper-colored, coarse marbling. The marbling often extends to the chin, throat and undersides of the forelimbs (Nussbaum 1976). Young metamorphs have bright, golden marbling. Larvae are the stream type and have short, bushy gills and a low tail fin that extends forward to the hindlimb insertion. Larval coloration is light brown above with a white to yellowish venter. The tail lacks the conspicuous blotching seen in larval D. tenebrosus. A yellow stripe is usually present behind the eyes and the tips of the digits are black and cornified (Petranka 1998).
 
On the basis of genetic differentiation, D. tenebrosus was recently recognized as a species distinct from D. ensatus (Good 1989). The genus Dicamptodon was historically included as a subfamily (Dicamptodontinae) in the family Ambystomatidae, and was placed in a separate family, Dicamptodontidae, based on features of the spinal nerves (Edwards 1976).

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