Oak Lawn, IL has a population of 56,774 and is the 701st largest city in the United States. The population density is 6,624 per sq mi which is 2880% higher than the Illinois average and 7211% higher than the national average. The median age in Oak Lawn is 41 which is approximately 9% higher than the Illinois average of 37. In Oak Lawn, 58% of the population over 15 years of age are married, 72% speak English and 13% speak Spanish. 77% of Oak Lawn residents were born in Illinois, 7% were born out of state, 1% were born outside of the United States and 16% were foreign born.