South Pekin, IL has a population of 1,140 and is the 14,341st largest city in the United States. The population density is 2,282 per sq mi which is 927% higher than the Illinois average and 2419% higher than the national average. The median age in South Pekin is 34 which is approximately 8% lower than the Illinois average of 37. In South Pekin, 61% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 87% of South Pekin residents were born in Illinois, 12% were born out of state, 0% were born outside of the United States and 1% were foreign born.