The Antler River is located in the Prairie Pothole Region of North America's Great Plains in south-eastern Saskatchewan and south-western Manitoba in Canada in an area known as Palliser's Triangle. Its source is in Saskatchewan's Moose Mountain Upland and it is a major tributary of the Souris River. As a result, its flood levels are monitored by the United States Geological Survey. In 2011, several communities along the river experienced abnormally severe spring flooding that resulted in damage to many bridges crossing the river. Near Carnduff, repairs were still ongoing months after the water level had subsided. The Antler River Recreation District is an association of communities in the south-western corner of Manitoba that are on or near the river and its related branches. Towns involved include Melita and Pierson.

Course

The river starts on the eastern side of Moose Mountain Upland, north-east of the lakes of Kenosee and White Bear (Carlyle). and drains much of the eastern side of the upland. From there, the river heads south. It crosses Highway 13 just east of Wauchope and Highway 601. From there it continues south along the same route as the 601, crossing Highway 361 just west of Alida. As the river nears Highway 18, it is joined by Auburnton Creek and starts to head in a more south-easterly direction, crossing Highway 18 between Carnduff and Carievale. It continues south-east until it crosses into Manitoba. Two miles after crossing into Manitoba, it crosses the Canada–United States border, near the Antler–Lyleton Border Crossing, into North Dakota. The closest community to the river in North Dakota is Antler. The rivers heads east paralleling the border for about three miles before going back into Manitoba. The river then heads north-east until it meets up with the Souris River upstream and south of Melita.

Dams

There are two small dams along the river. One is just north-west of Carnduff. The other is in North Dakota. The North Dakota dam is called Antler Creek Dam and there is a park there called Memorial Park.

Tributaries

Flora and fauna

The Antler River is located in the Great Plains ecoregion of North America. Purple Locoweed (Oxytropis lambertii) is known to be found in parts of the river valley.