South Wilmington is a city located in Grundy County Illinois. With a 2020 population of 636, it is the 791st largest city in Illinois and the 12279th largest city in the United States . South Wilmington is currently declining at a rate of -0.62% annually and its population has decreased by -6.61% since the most recent census, which recorded a population of 681 in 2010. South Wilmington reached it's highest population of in . Spanning over 0 miles, South Wilmington has a population density of 1,293 people per square mile.
The average household income in South Wilmington is $87,623 with a poverty rate of 7.75%. The median rental costs in recent years comes to $925 per month, and the median house value is $127,800. The median age in South Wilmington is 40.7 years, 38.5 years for males, and 43.5 years for females.