Military Department 4244 Montgomery Rd Ellicott City, MD 21043 Phone : (410) 465-5004 Business Category National Security Maryland State Government--military Department, Ellicott City Armory, Hq 121 Engineer Battalion Cbt Corps 4244 Montgomery Rd Ellicott City, MD 21043 Phone : (410) 465-5004 Business Category Government Offices & Public Schools