The Iceland Gull is a highly variable species for which taxonomic limits are not well defined. The American Ornithologists' Union (1998) checklist (and supplements through 2006) allows two races within North America: L. g. glaucoides, breeding in Greenland and wintering as far south as the northeastern United States, and L. g. kumlieni, breeding from Baffin Island north to Ellesmere Island and as far west as Coats Island in northern Hudson Bay (Gaston et al. 1986). The species intergrades with Thayer's Gull on northern Baffin Island and Southampton Island (Snell 1989; Gaston and Elliot 1990) and was considered conspecific with it by Godfrey (1986).
Only a small number of Iceland Gulls have been banded in Canada, and only one encounter of a Canadian-banded bird has been reported: a bird banded at Digges Sound, at the northern tip of the Ungava Peninsula, and found dead in its first winter near Burin, Newfoundland (record 1). There is one encounter of a bird banded in Greenland and encountered near Cartwright, Labrador, in November (record 2). If this bird was reared in Greenland, it presumably belonged to the nominate race.