Camarasaurus supremus is a species of sauropod dinosaur that lived during the Jurassic period in what is now the western United States.

C. supremus is the largest and geologically youngest species in its genus, and was contemporary with several other exceptionally large dinosaurs, such as Saurophaganax and Maraapunisaurus.

[11] The first specimens of Camarasaurus supremus known to science were found in the spring of 1877 by Oramel William Lucas, a schoolteacher in Cañon City.

[2] Cope believed it to be the largest terrestrial animal yet known[12] and a relative of large dinosaurs from Europe and the eastern United States, like Cetiosaurus and Anchisaurus.

[12] After receiving the original bones, Cope employed collectors who gathered more of the material which was described in detail in 1921 by Henry Osborn and Charles Mook.

[16] In 1877, John A. Ryder created a life-sized illustration of the skeleton of Camarasaurus supremus with guidance from Cope that was fifty feet long.

[2] Cope regarded Camarasaurus as a terrestrial, herbivorous reptile that he compared to the giraffe due to the length of its neck.

[2] For decades after its discovery, Camarasaurus supremus would remain a relatively obscure taxon compared to the more complete and more extensively figured sauropods discovered by Cope's opponent Othniel Marsh.

[2] In 1925, Charles W. Gilmore suggested that Camarasaurus (formerly Morosaurus) robustus was synonymous with C. supremus,[19] as did Theodore E. White in 1958.

[1][23] South of Garden Park, several potential C. supremus remains were found by the Denver Museum of Natural History in Tithonian strata.

[1] Its fossils are only known from the uppermost layers of the Morrison Formation, and it is rare, with only 4.5% of Camarasaurus specimens identified as belonging to the species.

[9] Based on fossils from Garden Park, C. supremus coexisted with the large, enigmatic diplodocoids Amphicoelias altus and Maraapunisaurus fragillimus, the latter of which may have been one of the largest dinosaurs ever to exist.

A changing climate may have facilitated the evolution of larger species towards the end of the depositional period of the Morrison Formation.