The largest countries of the continent, Canada and the United States, also contain well-defined and recognized regions. In the case of Canada these are (from east to west) Atlantic Canada, Central Canada, Canadian Prairies, the British Columbia Coast, and Northern Canada. These regions also contain many subregions. In the case of the United States – and in accordance with the US Census Bureau definitions – these regions are: New England, Mid-Atlantic, South Atlantic States, East North Central States, West North Central States, East South Central States, West South Central States, Mountain States, and Pacific States. Regions shared between both nations included the Great Lakes Region. Megalopolises have formed between both nations in the case of the Pacific Northwest and the Great Lakes Megaregion.