
South Wilmington
- County:
- Grundy County
- County Seat:
- No
- Area (mi²):
- 0.492
- State:
- Illinois
South Wilmington is a village located in Grundy County, Illinois. South Wilmington has a 2025 population of 723. South Wilmington is currently growing at a rate of 0.56% annually and its population has increased by 2.55% since the most recent census, which recorded a population of 705 in 2020.
The average household income in South Wilmington is $99,435 with a poverty rate of 6.45%. The median age in South Wilmington is 46.3 years: 42.7 years for males, and 47.7 years for females.