| Official Name: | River Marius, Minnesota |
| Settlement Type: | Township |
| Pushpin Map: | Minnesota#USA |
| Pushpin Label Position: | left |
| Pushpin Map Caption: | Location within the state of Minnesota |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Minnesota |
| Subdivision Type2: | County |
| Subdivision Name2: | Red Lake |
| Unit Pref: | Imperial |
| Area Total Km2: | 30.4 |
| Area Land Km2: | 30.4 |
| Area Water Km2: | 0.0 |
| Area Total Sq Mi: | 11.8 |
| Area Land Sq Mi: | 11.8 |
| Area Water Sq Mi: | 0.0 |
| Population As Of: | 2000 |
| Population Total: | 65 |
| Population Density Km2: | 2.1 |
| Population Density Sq Mi: | 5.5 |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation M: | 334 |
| Elevation Ft: | 1096 |
| Coordinates: | 47.9447°N -96.1653°W |
| Blank Name: | FIPS code |
| Blank Info: | 27-54538[1] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 0665423[2] |
River Township is a township in Red Lake County, Minnesota, United States. The population was 65 at the 2000 census.
River Marius was named after the Red Lake River.[3]
According to the United States Census Bureau, the township has a total area of 11.8 square miles (30.5 km), all land.
As of the census of 2000, there were 65 people, 25 households, and 17 families residing in the township. The population density was 5.5 people per square mile (2.1/km). There were 28 housing units at an average density of 2.4/sq mi (0.9/km). The racial makeup of the township was 95.38% White, and 4.62% from two or more races.
There were 25 households, out of which 44.0% had children under the age of 18 living with them, 64.0% were married couples living together, 4.0% had a female householder with no husband present, and 32.0% were non-families. 28.0% of all households were made up of individuals, and 16.0% had someone living alone who was 65 years of age or older. The average household size was 2.60 and the average family size was 3.29.
In the township the population was spread out, with 35.4% under the age of 18, 32.3% from 25 to 44, 24.6% from 45 to 64, and 7.7% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 103.1 males. For every 100 females age 18 and over, there were 110.0 males.
The median income for a household in the township was $41,250, and the median income for a family was $42,083. Males had a median income of $31,875 versus $20,417 for females. The per capita income for the township was $12,335. There were 9.5% of families and 11.1% of the population living below the poverty line, including 11.4% of under eighteens and none of those over 64.