Demarest, NJ has a population of 5,007 and is the 6,467th largest city in the United States. The population density is 2,421 per sq mi which is 242022% higher than the New Jersey average and 2572% higher than the national average. The median age in Demarest is 44 which is approximately 10% higher than the New Jersey average of 40. In Demarest, 73% of the population over 15 years of age are married, 68% speak English and 5% speak Spanish. 35% of Demarest residents were born in New Jersey, 38% were born out of state, 2% were born outside of the United States and 25% were foreign born.