Chantilly, VA has a population of 24,312 and is the 1,794th largest city in the United States. The population density is 2,028 per sq mi which is 960% higher than the Virginia average and 2138% higher than the national average. The median age in Chantilly is 37 which is approximately 3% lower than the Virginia average of 38. In Chantilly, 59% of the population over 15 years of age are married, 58% speak English and 12% speak Spanish. 31% of Chantilly residents were born in Virginia, 32% were born out of state, 2% were born outside of the United States and 35% were foreign born.