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.
Rainwater Basin
Starks first recognized that the larger of these basins are approximately elliptical to elongate in shape. The larger and semi-elliptical of these basins typically measure about by . Most basins are closed depressions that hold runoff from the surrounding landscape to form seasonal lakes and wetlands in them. Some of these basins have been naturally "breached", or drain to an outside watershed, and no longer hold precipitation run-off. Many of the large semi-elliptical to elliptical Rainwater Basins have a crescent-shaped ridge that Stark referred to as a "lunette" located on the southeast side of them. These distinctive ridges are about in relief.