Hudson Bay drainage basin
The Hudson Bay drainage basin is the drainage basin in northern North America where surface water empties into Hudson Bay and adjoining waters. Spanning an area of about , the basin is almost totally in Canada (spanning parts of the Prairies, central and northern Canada), with a small portion in the United States (in Montana, the Dakotas, and Minnesota). The watershed's headwaters are in part on the Continental Divide of the Americas, and the watershed'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. On the Continental Divide the basin is bounded at Triple Divide Peak to the south, and Snow Dome to the north.
Borders of Canada
The border begins at the northwesternmost point of Minnesota's Northwest Angle 49°23′N, 95°09′W, and proceeds in an easterly direction through the Angle Inlet into the Lake of the Woods. At 41°19′N, 94°48′W in the Lake of the Woods, the border turns to a southerly direction, and continues into the Rainy River. The border then follows the Rainy River to Rainy Lake, then subsequently through numerous small lakes, including Lake Namakan, Lac la Croix, and Sea Gull Lake, until reaching the Pigeon River, which leads it out into Lake Superior. The border continues through Lake Superior to Whitefish Bay. The border then proceeds through Whitefish Bay into the St. Mary's River, then into the North Channel, then, at 45°59′N 83°26′N, turns to a southerly direction into the False Detour Channel, and reaches Lake Huron. The border then heads in a southerly direction through Lake Huron until reaching the St. Clair River, which subsequently leads it to Lake St. Clair. The border then proceeds through Lake St. Clair, reaching the Detroit River, which leads it to Lake Erie. The border then proceeds through Lake Erie into the Niagara River, which leads into Lake Ontario. The border then proceeds in a northwesterly direction in Lake Ontario, then at 43°27′N, 79°12′W, the border makes a sharp turn to a north easterly direction. The border then reaches and proceeds through the St. Lawrence River. Finally, at 45°00′N, 74°40′E, the border splits from the St. Lawrence River and continues into Quebec. This border, going from west to east, is shared with the U.S. states of Minnesota, Michigan, Ohio, Pennsylvania, and New York.