Zimmerman Telegram
Over two years into the First World War, German Foreign Minister Arthur Zimmerman sent a secret coded telegram to German Minister to Mexico Heinrich von Eckardt. The message offered United States territory to Mexico in return for joining the German cause.
The coded message was intercepted and deciphered by British intelligence and given to American Ambassador to Britain Walter Page. After Germany began unrestricted submarine warfare on February 1, the telegram was made public in the United States. On April 6, 1917, the United States Congress formally declared war on Germany and its allies.
Zimmerman Telegram as received by the German Minister to Mexico, January 19, 1917. National Archives Identifier: 302025.
This telegram and surrounding correspondence are part of Record Group 59: General Records of the Department of State, Series: Central Decimal Files. This central file collected correspondence dealing with all activities of the Department of State from 1910 to 1963. Correspondents included diplomatic officers around the world, other government agencies, foreign governments, Congress, the President, and the public.