September 12, 1918: The St. Mihiel Offensive Launches
American troops trickled into France in 1917 and the early part of 1918, but a virtual tsunami of American soldiers arrived in mid-1918. The Navy’s Transport Service moved nearly 2.1 million men and women across the Atlantic during WWI and almost 1.4 million of them were transported between May and September 1918.
Given the limited number of American troops in Europe before the summer of 1918, American forces could do little themselves and largely fought under broader French command. As their numbers increased, however, the American First Army was formed under Gen. Jack Pershing’s command and they were given primary responsibility for two significant operations. The first of those operations was the reduction of the St. Mihiel Salient, which began 100 year ago today.
The Germans took the St. Mihiel Salient in 1914 and, despite repeated French attempts to reduce the salient over the next four years, the Germans had not budged. The plan called for the American forces to eliminate the salient and then shift the bulk of those troops sixty miles to the north over a two-week period to spearhead their second major effort, the Meuse-Argonne Offensive. The detailed plans for both offensives and the transfer of personnel and materiel were developed by Pershing’s Operations Officer, Col. George C. Marshall, who served as Chief of Staff of the U.S. Army during WWII and become more famous for a different plan as the Secretary of State in 1947.
A previous post told the story of the 91st Division and their experience being transported to France, arriving in Le Havre on July 23, before being sent to the Haute-Marne area for training. Despite completing only five of the expected ten weeks of in-country training, the 91st Division was ordered to march toward St. Mihiel on September 7.
The St. Mihiel Offensive launched on September 12, with eleven American divisions and one French division involved in the effort. By coincidence, the Germans, wanting to even up their lines, began withdrawing from the St. Mihiel Salient just as the offensive began. This resulted in German troops being scattered outside their fortifications with their artillery heading east, and they were unable to effectively defend the attack. The salient was eliminated in four days with 7,000 American casualties while the Germans lost 22,500 men, 15,000 of whom were taken prisoner.
The 91st Division was held in reserve five miles behind the front and did not become involved in action. After the First Army achieved its battle objectives without using reserve troops, the 91st Division left the area on September 16. The division headed to the Meuse-Argonne where it had orders to go over the top the morning of September 26.
The coming Meuse-Argonne Offensive was the largest battle ever fought by American forces, involving more than 1.2 million troops. No battle before or since had as many American troops involved and it remains the deadliest battle in American history. The American First Army achieved a limited objective in the St. Mihiel Offensive. It was now time for a full test in the Meuse-Argonne Offensive and the 91st Division would be at the point of the spear during the attack.
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