Burch (1975) cites distribution as Kamchatka (eastern Asia); Alaska; the whole Yukon River system of Alaska and Yukon Territory; Washington, Oregon, and possibly (not likely) California. Washington and Oregon records (Puget Sound, Upper Klamath Lake, Ten Mile Lake in Coos Bay, Flores Lake south of Bandon, Green Lake in Seattle, Skookumchuck River, Scatter Creek, Crescent Lake, Lake Leland, Whatcom Lake) are all historical and are derived from Henderson (1929). In Alaska, this species occurs from the Aleutian Islands and southwestern Alaska to northern and central interior and into the upper Yukon River drainage and Old Crow Basin, Yukon Territory (Clarke 1981, Nedeau et al. 2005). It may also occur in Oregon, California and Washington (Henderson 1929, Ingram 1948), but sites need verification (T. Frest pers. comm. 2003). It has also been reported from Kamchatka, Russia (Baxter 1983, Clarke 1981, Nedeau et al. 2005). In Russia, the species is known from Kamchatka and Chukotka peninsulas, northern part of Magdadan region and from Kurile Archipelago (Paramushir Island) (Zatrawkin and Bogatov 1987, Saenko et al. 2001).