Franklin Park, NJ has a population of 15,454 and is the 2,760th largest city in the United States. The population density is 5,933 per sq mi which is 593224% higher than the New Jersey average and 6449% higher than the national average. The median age in Franklin Park is 36 which is approximately 9% lower than the New Jersey average of 40. In Franklin Park, 53% of the population over 15 years of age are married, 58% speak English and 9% speak Spanish. 38% of Franklin Park residents were born in New Jersey, 19% were born out of state, 2% were born outside of the United States and 40% were foreign born.