Hudson Bay drainage basin

The Hudson Bay drainage basin is the drainage basin in northern North America where surface water empties into the Hudson Bay and adjoining waters. Spanning an area of about and with a mean discharge of about, the basin is almost entirely within Canada. It encompasses parts of the Canadian Prairies, Central Canada, and Northern Canada. A small area of the basin is in the northern part of the Midwestern United States.
The Hudson Bay drainage basin coincides almost completely with the former territory of Rupert's Land, claimed by the Hudson's Bay Company in the 17th century. It was an ideal area for the early North American fur trade.

Boundaries and limits

The Hudson Bay's connection to the Labrador Sea is at the Hudson Strait's mouth, between Resolution Island in the Qikiqtaaluk Region and Cape Chidley on the Labrador Peninsula. The watershed's headwaters to the south-west are on the Continental Divide of the Americas, bounded at Triple Divide Peak to the south, and Snow Dome to the north. The western and northern boundary of the watershed is the Arctic Divide, and the southern and eastern boundary is the Laurentian Divide.
The basin covers parts of the Canadian provinces and territories of Quebec, Ontario, Manitoba, Saskatchewan, and Alberta, Nunavut, and the Northwest Territories. U.S. states within the basin include Montana, South Dakota, North Dakota, and Minnesota.
Hudson Bay is often considered part of the Arctic Ocean. For example, the International Hydrographic Organization defines the Hudson Bay, with its outlet extending from 62.5 to 66.5 degrees north as being part of the Arctic Ocean, specifically "Arctic Ocean Subdivision 9.11". Other authorities include it with the Atlantic Ocean, in part because of its greater water budget connection.

The largest river system within the Hudson Bay drainage basin is the Nelson River. While the Nelson runs a relatively short from Lake Winnipeg to the Hudson Bay, its tributaries extend as far west as the Rocky Mountains. From the Hudson Bay to Nelson River's farthest tributary, the Bow River, it has a length of and a drainage basin of. Some significant rivers include the Saskatchewan, Saskatchewan River|North Saskatchewan], South Saskatchewan, Red, Assiniboine, and the Red Deer.
The following list of rivers includes the principal rivers draining into the Hudson, James, and Ungava Bays of the Hudson Bay drainage basin. The rivers are presented by coastline, clockwise, starting with the George River in north-eastern Quebec, just south of Cape Chidley and the entrance to the Atlantic Ocean.
;Rivers of Quebec
;Rivers of Ontario
;Rivers of Manitoba
;Rivers of Nunavut