Assessment was made of all available cranial specimens of wild Canis dating since the Blancan and prior to AD 1918 in the region east of the Great Plains and south of the Prairie Peninsula, Lakes Erie and Ontario, and the St. Lawrence River. The small wolf C. priscolatrans(= C. edwardii) of the early Irvingtonian seems unrelated to the modern red wolf (C. rufus), but gave rise to a lineage including the larger C. armbrusteri and culminating in C. dirus of the late Rancholabrean. A small wolf, possibly a descendant of the Eurasian C. mosbachensis, did not reappear in the east until near the end of the Rancholabrean. At the same time, the coyote (C. latrans) disappeared from the east, not to return until the small wolf was extirpated in the 20th century. Fragmentary remains of the small wolf, dating from around 10,000 and 2,000-200 ybp, show continuity with 14 complete, mostly modern, eastern skulls. Multivariate analysis indicates those 14 represent a well-defined species, C. rufus, distinct from large series of the western gray wolf (C. lupus) and coyote. There is no evidence that the red wolf originated as a hybrid of the latter two species, though early specimens from central Texas suggest it began to interbreed with C. latrans by about 1900. Three long-recognized red wolf subspecies appear valid: C. r. floridanus, Maine to Florida; C. r. gregoryi, south-central United States; and C. r. rufus, central and coastal Texas, southern Louisiana, and probably now represented in the captive/reintroduced populations. The subspecies C. lupus lycaon of southeastern Ontario and southern Quebec is statistically intermediate to C. rufus and western C. lupus, and may have resulted from natural hybridization of those two species. Such could explain how the red and gray wolf differ so sharply where their ranges meet in the west but morphologically approach one another in the east.