| Place Name | Big Sioux Township |
| Place Type | Township |
| ZIP Code(s) | 51109 57038 57049 68743 68776 |
| County | Union County |
| Area Code(s) | 605 |
| Timezone | Central Standard Time (CST) |
| Population (2021) | 4,520 |
| Majority Ethnicity | White 85.13% |
| Metro/Micro Stats Area | Sioux City, IA-NE-SD |
| US Congressional District(s) | South Dakota At-Large |
| State House Districts | 16 |
| State Senate Districts | 16 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 85.13% |
| African American | 0.97% |
| Hispanic | 1.37% |
| Asian | 5.08% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 7.44% |