FHSM VP-2139 is the proximal end of a right carpometacarpus of the Late Cretaceous toothed seabird, Ichthyornis sp. (Aves: Ichthyornithiformes), housed in the Sternberg Museum of Natural History, Hays Kansas. The specimen was found near the contact between the Carlile and Greenhorn Formations in southern Ellis County, Kansas. The specimen marks the oldest record of Ichthyornis in Kansas, and this report represents the first detailed account of this specimen. The estimated total “skeletal length” (from the beak tip to the pygostyle tip) and “skeletal wingspan” (between the right and left phalangeal tips) of the bird individual are 24 cm and 43 cm, respectively. The bird specimen is paleoecologically intriguing, because it occurred in an offshore deposit which formed during the maximum transgressive phase of the Greenhorn Cyclothem of the Late Cretaceous Western Interior Sea.