Grey wolves (Canis lupus) are widespread across the Holarctic. Here, the previously proposed hypothesis that extant North American wolves originate from multiple waves of colonization from Asia is tested, along with the hypothesis that land connections have been important in the evolutionary history of other isolated wolf populations in Japan. Results suggest that the mitogenomes of all living wolves in North America, including Mexican wolves, most likely derive from a single colonization event from Eurasia that expanded the grey wolf range into North America. This colonization occurred while a land bridge connected Eurasia and North America before the Cordilleran and Laurentide ice sheets fused in the Last Glacial Maximum, c. 23 ka, much more recent than predicted based on the fossil record. Pleistocene land bridges also facilitated the separate colonization of Hokkaido and the southern Japanese islands. Extant wolf lineages in North America derive from wolves that migrated into North America coincident with the formation of the most recent land bridge with Eurasia. The maternal lineages from earlier Pleistocene American wolves are not represented in living American wolves, indicating that they left no descendants. The timing of colonization of North America, Hokkaido and the southern Japanese islands corresponds to the changes in land connectivity as a consequence of changing sea level. informacion[at]ebd.csic.es: Koblmüller et al (2016) Whole mitochondrial genomes illuminate ancient intercontinental dispersals of grey wolves (Canis lupus). J Biogeogr 43: 1728–1738. doi:10.1111/jbi.12765