Garrison, MD has a population of 8,551 and is the 4,440th largest city in the United States. The population density is 2,707 per sq mi which is 471% higher than the Maryland average and 2888% higher than the national average. The median age in Garrison is 39 which is approximately 1% higher than the Maryland average of 38. In Garrison, 45% of the population over 15 years of age are married, 78% speak English and 7% speak Spanish. 51% of Garrison residents were born in Maryland, 29% were born out of state, 1% were born outside of the United States and 19% were foreign born.