The name North Water was coined by 19th century whalers, who knew it only in the spring. The Eskimos of the Thule and Etah districts have known it as a winter phenomenon restricting sledge travel but offering good hunting conditions. The mean conditions for Mar-June can now be figured from air observations since 1954 and satellite pictures of 1966-68. The north limit is extremely stable: a fast-ice bridge in a convex curve across the narrow head of Smith Sound which persists to late July-Aug, when a general break- up occurs in Kane Basin. The southern boundary is extremely variable and often poorly defined. There are no observations of a freeze-up date of winter extent of North Water.