| Official Name: | South Branch Township, 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: | Watonwan |
| Unit Pref: | Imperial |
| Area Total Km2: | 101.2 |
| Area Land Km2: | 101.2 |
| Area Water Km2: | 0.0 |
| Area Total Sq Mi: | 39.1 |
| Area Land Sq Mi: | 39.1 |
| Area Water Sq Mi: | 0.0 |
| Population As Of: | 2000 |
| Population Total: | 303 |
| Population Density Km2: | 3.0 |
| Population Density Sq Mi: | 7.8 |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation M: | 338 |
| Elevation Ft: | 1109 |
| Coordinates: | 43.895°N -94.5592°W |
| Blank Name: | FIPS code |
| Blank Info: | 27-61276[1] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 0665645[2] |
South Branch Township is a township in Watonwan County, Minnesota, United States. The population was 303 at the 2000 census.
South Branch Township was organized in 1869, and named after the South Fork Watonwan River.[3]
According to the United States Census Bureau, the township has a total area of 39.1 square miles (101.2 km), all land.
As of the census of 2000, there were 303 people, 112 households, and 86 families residing in the township. The population density was 7.8 people per square mile (3.0/km). There were 117 housing units at an average density of 3.0/sq mi (1.2/km). The racial makeup of the township was 96.04% White, 0.99% Black or African American, none Native American, none Asian, none Pacific Islander, 2.97% from other races. Hispanic or Latino of any race were 3.30% of the population.
There were 112 households, out of which 33.0% had children under the age of 18 living with them, 75.0% were married couples living together, 0.9% had a female householder with no husband present, and 23.2% were non-families. 18.8% of all households were made up of individuals, and 9.8% had someone living alone who was 65 years of age or older. The average household size was 2.71 and the average family size was 3.13.
In the township the population was spread out, with 30.0% under the age of 18, 3.6% from 18 to 24, 25.7% from 25 to 44, 22.4% from 45 to 64, and 18.2% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 103.4 males. For every 100 females age 18 and over, there were 107.8 males.
The median income for a household in the township was $35,625, and the median income for a family was $39,205. Males had a median income of $25,357 versus $18,438 for females. The per capita income for the township was $13,449. About 13.9% of families and 10.7% of the population were below the poverty line, including 4.1% of those under the age of eighteen and 8.9% of those 65 or over.