Bel Air, MD has a population of 10,211 and is the 3,883rd largest city in the United States. The population density is 3,362 per sq mi which is 609% higher than the Maryland average and 3611% higher than the national average. The median age in Bel Air is 42 which is approximately 9% higher than the Maryland average of 38. In Bel Air, 61% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 58% of Bel Air residents were born in Maryland, 35% were born out of state, 1% were born outside of the United States and 6% were foreign born.