De Soto, IL has a population of 1,658 and is the 12,120th largest city in the United States. The population density is 1,817 per sq mi which is 718% higher than the Illinois average and 1906% higher than the national average. The median age in De Soto is 38 which is approximately 3% higher than the Illinois average of 37. In De Soto, 49% of the population over 15 years of age are married, 96% speak English and 2% speak Spanish. 80% of De Soto residents were born in Illinois, 19% were born out of state, 0% were born outside of the United States and 0% were foreign born.