Abstract: In early 1991, when I was at the Canadian National Museum, Dr. D. A. Russell kindly provided me some hesperornithid fossils for study. The specimens were collected from Bylot Island, Canada. Hesperornis is largely restricted to North America, especially in the Niobrara Formation of the United States (Feduccia, 1996) The youngest individual of the genus, represented by a left tarsometatarsus, was recovered from Western Alberta in Canada (Fox, 1974). The hesperornithid fossils from the Bylot Island represent the latest record of the Hesperornithidae, and the northernmost occurrance so far. The large size and morphologic specializaion are the main cause for its extinction.