On what date was the World War I Unknown Soldier buried at Arlington National Cemetery?

The World War I Unknown Soldier was buried at Arlington National Cemetery on November 11, 1921.

The burial took place three years after the armistice that ended major fighting in World War I and two years after the first U.S. Armistice Day observance. The date was chosen because November 11 already carried national meaning as the anniversary of the armistice.

The unidentified service member was selected from several unknown American dead exhumed from European military cemeteries. The ceremony transformed an unknown individual into a symbolic representative of all Americans whose remains were never identified.

The monument later came to include unknown service members from other conflicts. The World War I burial is therefore both a specific 1921 event and a foundation of Arlington’s continuing national remembrance tradition.