Trenton, NJ has a population of 84,559 and is the 401st largest city in the United States. The population density is 11,180 per sq mi which is 1117890% higher than the New Jersey average and 12240% higher than the national average. The median age in Trenton is 34 which is approximately 15% lower than the New Jersey average of 40. In Trenton, 36% of the population over 15 years of age are married, 61% speak English and 33% speak Spanish. 54% of Trenton residents were born in New Jersey, 16% were born out of state, 5% were born outside of the United States and 25% were foreign born.