Marlow Heights, MD has a population of 5,755 and is the 5,912th largest city in the United States. The population density is 2,831 per sq mi which is 497% higher than the Maryland average and 3025% higher than the national average. The median age in Marlow Heights is 37 which is approximately 5% lower than the Maryland average of 38. In Marlow Heights, 40% of the population over 15 years of age are married, 91% speak English and 5% speak Spanish. 19% of Marlow Heights residents were born in Maryland, 71% were born out of state, 1% were born outside of the United States and 9% were foreign born.