The Laurentian Divide divides water from the Artic and Hudson Bay from water that directly enters the Atlantic(through the St Lawrence, East Coast or Gulf of Mexico). If you consider Hudson Bay part of the Artic Ocean, the Laurentian Divide is major and separates the Artic Ocean watershed from the Atlantic watershed. If you consider Hudson Bay to be part of the Atlantic(which most do), then the Laurentian Divide is a minor divide which separates the Hudson Bay watershed from the St Lawrence watershed. Roughly half of ND lies on each side of the divide. Roughly a diagonal from the NW corner of the state to the SE.