Havre De Grace Sr High School 700 Congress Ave Havre De Grace, MD 21078 Phone : (410) 939-6600 Business Category Schools Schools-Public Schools-Senior High Harford County--pupil Services, Schools, Havre De Grace High Havre De Grace, MD 21078 Phone : (410) 939-6600 Business Category Schools Government Offices-County Government Offices & Public Schools Harford County--schools, Schools, Havre De Grace High Havre De Grace, MD 21078 Phone : (410) 939-6600 Business Category Schools Government Offices-County Government Offices & Public Schools