| Official Name: | River Sioux, Iowa |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Iowa#USA |
| Pushpin Label: | River Sioux |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Harrison |
| Subdivision Type3: | Township |
| Subdivision Name3: | Little Sioux |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 0.99 |
| Area Land Km2: | 0.99 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 0.38 |
| Area Land Sq Mi: | 0.38 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 42 |
| Population Density Km2: | 42.61 |
| Population Density Sq Mi: | 110.24 |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 1040 |
| Coordinates: | 41.8058°N -96.0464°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 51545[2] |
| Area Code: | 712 |
| Blank Name: | FIPS code |
| Blank Info: | 19-67530 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 460651 |
River Sioux is an unincorporated community and census-designated place in Harrison County, Iowa, United States. As of the 2020 Census the population was 42.
River Sioux was platted in 1868 when the railroad was extended to that point.[3] It was named after the nearby Little Sioux River.[4]
River Sioux is zoned to the West Harrison Community School District.[5]
As of the census of 2020,[6] there were 42 people, 17 households, and 7 families residing in the community. The population density was 110.4 inhabitants per square mile (42.6/km2). There were 28 housing units at an average density of 73.6 per square mile (28.4/km2). The racial makeup of the community was 95.2% White, 0.0% Black or African American, 0.0% Native American, 0.0% Asian, 0.0% Pacific Islander, 0.0% from other races and 4.8% from two or more races. Hispanic or Latino persons of any race comprised 4.8% of the population.
Of the 17 households, 17.6% of which had children under the age of 18 living with them, 35.3% were married couples living together, 5.9% were cohabitating couples, 41.2% had a female householder with no spouse or partner present and 17.6% had a male householder with no spouse or partner present. 58.8% of all households were non-families. 58.8% of all households were made up of individuals, 29.4% had someone living alone who was 65 years old or older.
The median age in the community was 48.0 years. 33.3% of the residents were under the age of 20; 0.0% were between the ages of 20 and 24; 9.5% were from 25 and 44; 28.6% were from 45 and 64; and 28.6% were 65 years of age or older. The gender makeup of the community was 64.3% male and 35.7% female.