Catonsville is an unincorporated community and a census-designated place in Baltimore County, Maryland, United States. The population was 39,820 at the 2000 census. Catonsville is bordered by Woodlawn to the north, by the City of Baltimore to the east, by Elkridge to the south, and by Ellicott City to its west. Catonsville apartments for rent comparison page shows most up to date rent information on Catonsville apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.