The type species, Niobrarasaurus coleii, was discovered and collected in 1930 by a geologist named Virgil Cole. It was originally described by Mehl in 1936 and named Hierosaurus coleii. It was then re-described as a new genus by Carpenter et al. in 1995. In 2002 the type specimen was transferred to the Sternberg Museum of Natural History, Hays, Kansas.