Diceratherium (meaning "two horned beast") is an extinct genus of rhinocerotid native to North America during the Oligocene through Miocene living from 33.9 to 11.6 mya, existing for approximately 22.3 million years.

It was assigned to Rhinocerotidae by Marsh (1875) and Carroll (1988); to Diceratheriinae by Prothero (1998); to Aceratheriinae by Weidmann and Ginsburg (1999); and to Teleoceratini by Sach and Heizmann (2001).

[6] A full-body mold of a Diceratherium exists as an impression in a cliff on the shore of Blue Lake near Coulee City, Washington.

[7] The impression is a lava cast that is thought to be of a mature individual that died in a shallow lake and was rapidly buried by a basalt flow during the mid-Miocene (about 15 million years ago), creating a three-dimensional mold of its body.

[8] The mold formed a rhinoceros-shaped cave on exposed rocks belonging to the Columbia River Basalt Group, which was first discovered by two Seattle couples searching for petrified wood in 1935, who also discovered remnant bones of the animal.