For more than 130 years, the type locality of the Plains Spotted Skunk, Spilogale putorius interrupta (Rafinesque, 1820) has been accepted to be along the upper Missouri River. The species' description was based on a specimen observed by Constantine S. Rafinesque during his 1818 exploration of the Ohio River Valley, but Rafinesque never ventured into the animal's geographic range west of the Mississippi River, calling into question the type locality and, therefore, the identity of the taxon. We reconstruct Rafinesque's itinerary from his notes, publications, and correspondence and determine that Rafinesque probably observed the specimen on 20 September in Middletown, Kentucky, while traveling between Louisville and Lexington. He spent the day with John Bradbury, who participated in the 1811 Astor expedition up the Missouri River. On 1 April 1811, Bradbury collected the skin of a skunk, and evidence suggests that it was this skin that Rafinesque described. The type specimen of the Plains Spotted Skunk was obtained on the Missouri River flood plain in southern Chariton County or northern Saline County, Missouri, and this area should be considered the type locality for M. interrupta.