The Mustinka River is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of Lake Traverse

Lake Traverse

Lake Traverse is the southernmost body of water in the Hudson Bay watershed of North America. It lies along the border between the U.S. states of Minnesota and South Dakota...

, 68 mi (109 km) long, in western Minnesota

Minnesota

Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. Via Lake Traverse, the Bois de Sioux River

Bois de Sioux River

The Bois de Sioux River drains Lake Traverse, the southernmost body of water in the Hudson Bay watershed of North America. It is a tributary of the Red River of the North and defines part of the western border of the U.S. state of Minnesota, and the eastern borders of North Dakota and South Dakota...

, the Red River of the North

Red River of the North

The Red River is a North American river. Originating at the confluence of the Bois de Sioux and Otter Tail rivers in the United States, it flows northward through the Red River Valley and forms the border between the U.S. states of Minnesota and North Dakota before continuing into Manitoba, Canada...

, Lake Winnipeg

Lake Winnipeg

Lake Winnipeg is a large, lake in central North America, in the province of Manitoba, Canada, with its southern tip about north of the city of Winnipeg...

, and the Nelson River

Nelson River

The Nelson River is a river of north-central North America, in the Canadian province of Manitoba. Its full length is , it has mean discharge of , and has a drainage basin of , of which is in the United States...

, it is part of the watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 of Hudson Bay

Hudson Bay

Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

. The river drains an area of 909 square miles (2,354.3 km²).

Course

The Mustinka River rises about 5 miles (8 km) south-southwest of Fergus Falls

Fergus Falls, Minnesota

Fergus Falls is a city in and the county seat of Otter Tail County, Minnesota, United States. The population was 13,138 at the 2010 census.-Today:...

 in southwestern Otter Tail County

Otter Tail County, Minnesota

Otter Tail County is a county located in the U.S. state of Minnesota. As of 2010, the population was 57,303. Its county seat is Fergus Falls.-History:...

 and initially flows generally southward into Grant County

Grant County, Minnesota

As of the census of 2000, there were 6,289 people, 2,534 households, and 1,740 families residing in the county. The population density was 12 people per square mile . There were 3,098 housing units at an average density of 6 per square mile...

, passing through Stony Brook Lake and Lightning Lake. The river turns westwardly in southern Grant County and flows past Norcross

Norcross, Minnesota

Norcross is a city in Grant County, Minnesota, United States, along the Mustinka River. The population was 70 at the 2010 census.-Geography:According to the United States Census Bureau, the city has a total area of , all of it land....

 into Traverse County

Traverse County, Minnesota

As of the census of 2000, there were 4,134 people, 1,717 households, and 1,129 families residing in the county. The population density was 7 people per square mile . There were 2,199 housing units at an average density of 4 per square mile...

, where it turns southwestward past Wheaton

Wheaton, Minnesota

As of the census of 2000, there were 1,619 people, 747 households, and 434 families residing in the city. The population density was 909.2 people per square mile . There were 907 housing units at an average density of 509.4 per square mile...

. It flows into the northern end of Lake Traverse from the west, about 7 miles (11 km) southwest of Wheaton.

Much of the river's lower course has been straightened and channelized.