Deal Island, MD has a population of 443 and is the 20,309th largest city in the United States. The population density is 146 per sq mi which is 69% lower than the Maryland average and 61% higher than the national average. The median age in Deal Island is 59 which is approximately 54% higher than the Maryland average of 38. In Deal Island, 78% of the population over 15 years of age are married, 97% speak English and 0% speak Spanish. 67% of Deal Island residents were born in Maryland, 31% were born out of state, 0% were born outside of the United States and 1% were foreign born.