Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Formerly throughout North America south through much of Mexico; also Europe and Asia. Replaced by the red wolf in the southeastern United States. Today found south of Canada only in northern Mexico (no recent confirmed reports; extirpated or maybe a few in eastern Sonora, Chihuahua, and/or Zacatecas?), a few areas in the Rocky Mountains (northwestern Montana, reintroduction sites in Wyoming and Idaho), northwestern Great Lakes region (northeastern third of Minnesota, northern Wisconsin, Michigan Upper Peninsula), and Cascade Mountains of northern Washington. Formerly much more numerous in the Rocky Mountain states than in the southwestern U.S. (Johnson 1991). Extirpated in much of southern Canada (see Theberge  and Can. Field-Nat. 106:138 for range/status map); remains in 85% of former total Canadian range (Theberge 1991).
In 1995, wolf reintroductions were initiated in the Yellowstone ecosystem and in central Idaho (nonessential experimental populations) (USFWS 1994; Federal Register, 16 August 1994; Bangs and Fritts 1993; End. Sp. Bull. 20(4):4-5). See Bangs et al. (1998) for information on the status of gray wolf restoration in Montana, Idaho, and Wyoming. In 1998, USFWS (Federal Register, 12 January 1998) announced its intention to reintroduce the Mexican gray wolf (subspecies baileyi) into Arizona and New Mexico (Apache and Gila national forests, also possibly White Sands Missile Range).
Wolf observations in the Dakotas have increased in recent years, likely related to range expansion and population increases in adjacent areas, especially Minnesota; most occurrences have been of young individuals, suggesting dispersal (Licht and Fritts 1994).
Grewal et al. (2004) used genetic data to determine that the wolf population in Algonquin Provincial Park in Ontario, Canada, is a southern part of a larger metapopulation of Canis lycaon (or Canis lupus lycaon).