The Snake 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 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...

 in northwestern 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...

. It is one of three streams in Minnesota with this name (see Snake River (Minnesota)).

Course

The Snake River is 91 miles (146.4 km) long and with its tributaries drains a 1324 square miles (3,429.1 km²) area. It flows for its entire length on the old lake bed of glacial Lake Agassiz

Lake Agassiz

Lake Agassiz was an immense glacial lake located in the center of North America. Fed by glacial runoff at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined, and it held more water than contained by all lakes in the world today.-Conception:First...

, mostly in western Marshall County

Marshall County, Minnesota

Marshall County is a county located in the U.S. State of Minnesota. In 2010, the population was 9,439. It's county seat is Warren.-Geography:...

 but also through a small portion of northwestern Polk County

Polk County, Minnesota

As of the census of 2000, there were 31,369 people, 12,070 households, and 8,050 families residing in the county. The population density was 16 people per square mile . There were 14,008 housing units at an average density of 7 per square mile...

. After initially flowing southwestwardly from its headwaters, the Snake turns westward and collects a short tributary, the South Branch Snake River, and passes the towns of Warren

Warren, Minnesota

As of the census of 2000, there were 1,678 people, 699 households, and 432 families residing in the city. The population density was 1,174.1 people per square mile . There were 785 housing units at an average density of 549.3 per square mile...

 and Alvarado

Alvarado, Minnesota

Alvarado is a city situated along the Snake River in Marshall County in the U.S. state of Minnesota. The population was 363 at the 2010 census.Minnesota Highway 1 and Minnesota Highway 220 are two of the main arterial routes in the community.-Geography:...

. Downstream of Alvarado, the Snake turns north-northwestward, paralleling the Red River in the Red River Valley

Red River Valley

The Red River Valley is a region in central North America that is drained by the Red River of the North. It is significant in the geography of North Dakota, Minnesota, and Manitoba for its relatively fertile lands and the population centers of Fargo, Moorhead, Grand Forks, and Winnipeg...

. Much of the river's course through the valley has been straightened and channelized. It collects the Middle River

Middle River (Minnesota)

The Middle River is a tributary of the Snake River in northwestern Minnesota in the United States. It flows for its entire length in Marshall County.-Course:...

 upstream of its confluence with the Red in Fork Township

Fork Township, Minnesota

Fork Township is a township in Marshall County, Minnesota, United States. The population was 14 at the 2000 census.-Geography:According to the United States Census Bureau, the township has a total area of , of which, of it is land and of it is water.-Demographics:As of the census of 2000, there...

.