Franklin Park, IL has a population of 18,290 and is the 2,385th largest city in the United States. The population density is 3,835 per sq mi which is 1625% higher than the Illinois average and 4133% higher than the national average. The median age in Franklin Park is 39 which is approximately 5% higher than the Illinois average of 37. In Franklin Park, 55% of the population over 15 years of age are married, 42% speak English and 39% speak Spanish. 60% of Franklin Park residents were born in Illinois, 5% were born out of state, 1% were born outside of the United States and 34% were foreign born.