Heptodon was named by Cope (1882). It was considered paraphyletic by Colbert (2005). It was assigned to Helaletinae by Radinsky (1966); to Ceratomorpha by Cope (1882) and Colbert and Schoch (1998); to Heptodontidae by Holbrook (1999); and to Tapiroidea by Colbert (2005). M. W. Colbert. 2005.
Heptodon was about 1 metre (3.3 ft) in length, and closely resembled modern tapirs. The shape of the skull suggests that it probably lacked the characteristic tapir trunk. Instead it probably had a slightly elongated, fleshy upper lip, like its relative Helatetes.
A single specimen was examined by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass. It was estimated to have a weight of 15.5 kg (34 lb).