The Klaipėda Region or Memel Territory was defined by the 1919 Treaty of Versailles in 1920 and refers to the northernmost part of the German province of East Prussia, when, as Memelland, it was put under the administration of the Entente's Council of Ambassadors. The Memel Territory, together with other areas severed from Germany, was to remain under the control of the League of Nations until a future date, when the people of these regions would be allowed to vote on whether the land would return to Germany or not. Today, the former Memel Territory is controlled by Lithuania as part of Klaipėda and Tauragė counties.

The Treaty of Versailles was a peace treaty signed on 28 June 1919. As the most important treaty of World War I, it ended the state of war between Germany and most of the Allied Powers. It was signed in the Palace of Versailles, exactly five years after the assassination of Archduke Franz Ferdinand, which led to the war. The other Central Powers on the German side signed separate treaties. Although the armistice of 11 November 1918 ended the actual fighting, and agreed certain principles and conditions including the payment of reparations, it took six months of Allied negotiations at the Paris Peace Conference to conclude the peace treaty. Germany was not allowed to participate in the negotiations before signing the treaty.