Souris River

Souris River Mouse River, Rivière Souris
The river in the town of Souris, Manitoba
The Red River drainage basin, with the Souris River highlighted
Location
Countries	Canada United States
Provinces	Manitoba Saskatchewan
State	North Dakota
Cities	Minot, ND Souris, MB Weyburn, SK Melita, MB
Physical characteristics
Source	north of Weyburn
• location	Saskatchewan
• coordinates	49°49′53″N 103°47′46″W / 49.83139°N 103.79611°W / 49.83139; -103.79611
Mouth	Assiniboine River
• location	Manitoba, Canada
• coordinates	49°39′54″N 99°34′07″W / 49.66500°N 99.56861°W / 49.66500; -99.56861
Length	435 mi (700 km)
Basin size	23,600 sq mi (61,000 km2)
Discharge
• location	Weyburn, SK; river mile 97.9 (river kilometre 157.6)
Basin features
River system	Red River drainage basin
Tributaries
• left	Antler
• right	Gainsborough
[1][2]

The Souris River (/ˈsʊərɪs/; French: rivière Souris) or Mouse River (as it is alternatively known in the U.S., a translation of its French name) is a river in central North America. Approximately 435 miles (700 km) in length, it drains about 23,600 square miles (61,100 km²) in Canada and the United States.

Rising in southern Saskatchewan in the Yellow Grass Marshes north of Weyburn, the river wanders southeast into the U.S. through North Dakota beyond Minot to its most southern point at Velva, and then back north into Canada in southwestern Manitoba.

Flowing east, it passes through the communities of Melita, Hartney, Souris, and Wawanesa, Manitoba, prior to the confluence with the Assiniboine River near Treesbank, about 25 miles (40 km) southeast of Brandon. The main tributaries of the Souris in Manitoba are the Antler River, Gainsborough Creek, and Plum Creek. The elevation at the confluence is approximately 1,120 feet (340 m) above sea level.

At the end of the last ice age, over 10,000 years ago, the rapid draining of former Glacial Lake Regina eroded a large channel that is now occupied by the much smaller contemporary Souris River.^[3] Also, much of the drainage basin is fertile silt and clay deposited by another former glacial lake, Lake Souris.