Twenty-eight countries were members of the League of Nations for its entire existence. Another 35 countries joined or withdrew at various times.
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Countries are listed under the year they joined. Countries with the word "withdrew" next to them indicate the country left under their own choice. Countries with the word "left" next to them are countries that ceased to be because of annexation by either Germany or Italy. The USSR was the only country to be expelled by the League. The United States never joined the League of Nations.