U.S. Citizenship & Naturalization Services - Baltimore District Office is located at 31 Hopkins Place, Fallon Federal Bldg., Baltimore, MD 21201. U.S. Citizenship & Naturalization Services - Baltimore District Office can be reached by their main phone number at +1 (800) 375-5283. Alternatively, you can reach U.S. Citizenship & Naturalization Services - Baltimore District Office by phone at +1 (800) 767-1833. Visit the U.S. Citizenship & Naturalization Services - Baltimore District Office website by clicking here.