The Lakota Formation is a sequence of rocks of early Cretaceous (Berriasian to Barremian) age from Western North America.

Located in South Dakota, the name of the formation is derived from the Lakota Native American tribe.

"[3] An ankylopollexian iguanodont Hoplitosaurus H. marshi Chilson Member "Partial postcranial skeleton [and] osteoderms.

"[4] An ankylosaur belonging to Polacanthidae Osmakasaurus[5][6] O. depressus Chilson Member Portions of both ilia, anterior part of the blade of one pubis, an incomplete sacrum, centrum of the last sacro-dorsal, 12 caudal vertebrae, 1 thoracic rib and many fragments An ankylopollexian iguanodont Macronaria[7] Chilson Member Left humerus and right metacarpal I A macronarian related to Camarasaurus Bolodon B. hydei[8] Chilson Member Right M2 A plagiaulacid multituberculate Infernolestes[8] I. rougieri Chilson Member Right lower M1 A spalacotheriid trechnotherian.

A dryolestid Passumys[8] P. angelli Chilson Member Right M1 Other vertebrate remains found within the Lakota Formation include a fish scale from the gar Lepisosteus and a crocodile tooth [10]