The American Expeditionary Forces' first independent Offensive in the First World War.
The St Mihiel Offensive, which took place between the 12th and 16th September 1918, was the first full scale attack that was under the direct command of the Americans, in the person of General J Pershing. He combined his command of the First (at the time the only) American Army with that of Commander in Chief of the AEF, a tremendous burden.