Florence, NJ has a population of 4,366 and is the 7,047th largest city in the United States. The population density is 3,496 per sq mi which is 349489% higher than the New Jersey average and 3759% higher than the national average. The median age in Florence is 43 which is approximately 8% higher than the New Jersey average of 40. In Florence, 56% of the population over 15 years of age are married, 92% speak English and 3% speak Spanish. 75% of Florence residents were born in New Jersey, 20% were born out of state, 1% were born outside of the United States and 4% were foreign born.