Barnesville, MD has a population of 152 and is the 25,610th largest city in the United States. The population density is 311 per sq mi which is 34% lower than the Maryland average and 243% higher than the national average. The median age in Barnesville is 48 which is approximately 25% higher than the Maryland average of 38. In Barnesville, 66% of the population over 15 years of age are married, 91% speak English and 6% speak Spanish. 35% of Barnesville residents were born in Maryland, 57% were born out of state, 2% were born outside of the United States and 6% were foreign born.