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.
Carpenter, K., D. Dilkes, and D. B. Weishampel. 1995. The dinosaurs of the Niobrara Chalk Formation (upper Cretaceous, Kansas), Journal of Vertebrate Paleontology 15(2): 275-297.
Carpenter, K. and Everhart, M. J. 2007. Skull of the ankylosaur Niobrarasaurus coleii (Ankylosauria: Nodosauridae) from the Smoky Hill Chalk (Coniacian) of western Kansas. Kansas Academy of Science, Transactions, 110(1/2): 1-9
Cole, V. B. 2007. Field notes regarding the 1930 discovery of the type specimen of Niobrarasaurus coleii, Gove County, Kansas. Kansas Academy of Science, Transactions 110(1/2): 132-134.
Everhart, M. J. 2004. Notice of the transfer of the holotype specimen of Niobrarasaurus coleii (Ankylosauria; Nodosauridae) to the Sternberg Museum of Natural History. Kansas Academy of Science, Transactions 107(3-4): 173-174.
Everhart, M. J. and S. A. Hamm. 2005. A new nodosaur specimen (Dinosauria: Nodosauridae) from the Smoky Hill Chalk (Upper Cretaceous) of western Kansas. Kansas Academy of Science, Transactions 108(1/2): 15-21.
Liggett, G. A. 2005. A review of the dinosaurs from Kansas. Kansas Academy of Science. Transactions 108(1/2): 1-14.
Mehl, M. G. 1931. Aquatic dinosaur from the Niobrara of western Kansas. Bulletin of the Geological Society of America 42: 326-327.
Mehl, M. G. 1936. Hierosaurus coleii: a new aquatic dinosaur from the Niobrara Cretaceous of Kansas. Denison University Bulletin, Journal of the Scientific Laboratory 31: 1-20, 3 pls.