Mokena, IL has a population of 19,839 and is the 2,193rd largest city in the United States. The population density is 2,208 per sq mi which is 893% higher than the Illinois average and 2337% higher than the national average. The median age in Mokena is 40 which is approximately 8% higher than the Illinois average of 37. In Mokena, 66% of the population over 15 years of age are married, 93% speak English and 2% speak Spanish. 84% of Mokena residents were born in Illinois, 10% were born out of state, 1% were born outside of the United States and 5% were foreign born.