Catonsville, MD has a population of 42,027 and is the 974th largest city in the United States. The population density is 3,010 per sq mi which is 380% higher than the Maryland average and 3223% higher than the national average. The median age in Catonsville is 39 which is approximately 2% higher than the Maryland average of 38. In Catonsville, 55% of the population over 15 years of age are married, 90% speak English and 3% speak Spanish. 64% of Catonsville residents were born in Maryland, 27% were born out of state, 1% were born outside of the United States and 8% were foreign born.