The Battle of Saint-Mihiel was a major World War I battle fought from 12 to 16 September 1918, involving the American Expeditionary Forces (AEF) and 110,000 French troops under the command of General John J. Pershing of the United States against German positions. The U.S. Army Air Service played a significant role in this action.

This battle marked the first use of the terms "D-Day" and "H-Hour" by the Americans. The attack on Metz was not realized, as the Supreme Allied Commander Ferdinand Foch ordered the American troops to march towards Sedan and Mézières, which would lead to the Meuse–Argonne offensive.

Background: The Saint-Mihiel salient

Saint-Mihiel is a town in the Meuse department in northeastern France. After the end of the 1870–71 Franco-Prussian War, the town was no longer considered important strategically, and France did not develop military installations. This changed early in World War I, when the town was inside the battlefront.

In 1914, the German command wished to take the Verdun fortifications, which formed a strong point in the French lines. A first attempt, at Bois-le-Pretre (Priesterwald in German), failed, despite violent fighting. During two more attempts (Battle of Flirey), German troops took Saint-Mihiel and Fort du Camp-des-Romains, but they were ultimately stopped at Fort de Troyon to the south of Verdun.

During the course of the war, the front did not change much in this area. Saint-Mihiel formed a salient inside the French lines, blocking communications between Nancy and Verdun. The area near St. Mihiel suffered much fighting:

  • The Crête des Éparges (Les Éparges crest): February–April 1915.
  • At the Bois d'Ailly (Ailly Wood) and the Tranchée de la Soif (Trench of Thirst): isolated behind German lines, Commander d'André's men fought three days without food or water before surrendering in May 1915.
  • At Bois Brûlé (The Burned Forest), the French suffered many casualties when German conquered a redoubt in December 1914. It was here that the sub-officer Jacques Péricard pronounced the famous words: "Debout les morts!" (Dead men, arise!) on 8 April 1915.
  • The forêt d'Apremont (Apremont forest), the Tête à vache (Cow's head) trenches, Calonne trenches...

In spite of French attacks, the German forces were able to retain this strategic location until the last months of the war.

Prelude

thumb|[[John J. Pershing|General Pershing]]

General John Pershing thought that a successful Allied attack in the region of St. Mihiel, Metz, and Verdun would have a significant effect on the German Army. Pershing had to persuade Marshal Foch (the supreme Allied military commander) to permit an American attack on the salient.

Weather reports

The weather corps of Corps I Operation Order stated: "Visibility: Heavy driving wind and rain during parts of day and night. Roads: Very muddy."

German defensive positions

thumb|right|Map of the Battle

Prior to the American operation, the Germans installed many in-depth series of trenches, wire obstacles, and machine-gun nests. The Allied forces discovered the information on a written order to Army Group Gallwitz. As a result, by September 1918, Lieutenant Colonel George S. Patton Jr. had finished training two tank battalions – 144 French-built Renault FT light tanks organized as the 344th and 345th Battalions of the United States Tank Corps – at Langres, France for an upcoming offensive at the St. Mihiel salient. "Due to the serious resistance of the enemy, especially along the eastern edge of the FORET d’ARGONNE and in the vicinity of CHEPPY and VARENNES, and due also the lack of support of the Infantry, all the Tanks had contrary to plan entered the action before evening of the first day. The 344th Battalion left the positions of departure and advanced ahead of the Infantry at H-hour (5:30 a.m.) On the morning of the 26th, Colonel G. S. Patton, Jr., commanding the Brigade of Tanks, was wounded while getting Tanks forward and rallying disorganized Infantrymen to attack enemy resistance. Major Sereno E. Brett, commanding the 344th Battalion, was then placed in command of the Brigade." Patton was awarded the Distinguished Service Cross for his "extraordinary heroism" that day.

Allied air support

thumb|220x220px|Lieutenant [[Eddie Rickenbacker at St. Mihiel.]]

Chief of the United States Army Air Service Mason Patrick oversaw the organization of 28 air squadrons for the battle, with the French, British, and Italians contributing additional units to bring the total force numbers to 701 pursuit planes, 366 observation planes, 323 day bombers, and 91 night bombers. The 1,481 total aircraft made it the largest air operation of the war.

The French Army engaged the newly created Division Aérienne (Air Division), under command of General Duval, with a strength of 717 planes (24 fight squadron / 432 SPAD VII, 15 Close Air Support squadron / 225 BREGUET XIV, 4 reconnaissance squadron / 60 CAUDRON R XI). Five French fighter groups and 3 US Army fighter / bomber groups were also engaged.

Battle

thumb|right|250px|Columns of German prisoners taken by the Americans in the first day of the assault on the St. Mihiel salient, marching in the rain toward the prison pens prepared for them at [[Ansauville, France.]]

The Saint-Mihiel offensive began on 12 September with a threefold assault on the salient. The main attack was made against the south face by two American corps. On the right was the I Corps (from right to left the 82nd, 90th, 5th, and 2nd Divisions in line with the 78th in reserve) covering a front from Pont-à-Mousson on the Moselle west toward Limey; on the left, the IV Corps (from right to left the 89th, 42d, and 1st Divisions in line with the 3rd in reserve) extending along a front from Limey west toward Marvoisin. A secondary thrust was carried out against the west face along the heights of the Meuse, from Mouilly north to Haudimont, by the V Corps (from right to left the 26th Division, the French 15th Colonial Division, and the 8th Brigade, 4th Division in line with the rest of the 4th in reserve). A holding attack against the apex, to keep the enemy in the salient, was made by the French II Colonial Corps (from right to left the French 39th Colonial Division, the French 26th Division, and the French 2nd Cavalry Division in line). In First Army reserve were the American 35th, 80th, and 91st Divisions.

The American V Corps location was at the northwestern vertices, the II French Colonial Corps at the southern apex, and the American IV and I Corps at the southeastern vertices of the salient.

Defending the salient was German "Army Detachment C", consisting of eight divisions and a brigade in the line and about two divisions in reserve. Now desperately short of manpower, they had begun a step-by-step withdrawal from the salient only the day before the offensive began.

Pershing's plan had tanks supporting the advancing infantry, with two tank companies interspersed into a depth of at least three lines, and a third tank company in reserve. The result of the detailed planning was an almost unopposed assault into the salient.

First United States Army – Gen. John J Pershing

  • I Corps: Maj Gen Hunter Liggett
  • Headquarters Observation Group
  • 2nd Balloon Company
  • 5th Balloon Company
  • 82nd Division – Maj Gen William P. Burnham
  • 50th Aero Squadron (split duty)
  • 42nd Balloon Company (split duty)
  • 90th Division – Maj Gen Henry Tureman Allen
  • 50th Aero Squadron (split duty)
  • 42nd Balloon Company (split duty)
  • 5th Division – Maj Gen John E. McMahon
  • 12th Aero Squadron
  • 1st Balloon Company
  • 2nd Division – Maj Gen John A. Lejeune
  • 1st Aero Squadron
  • 1st Balloon Company
  • 78th Division (Corps Reserve) – Maj Gen James H McRae
  • IV Corps – Maj Gen Joseph T. Dickman
  • Headquarters Observation Group
  • 69th Balloon Company
  • 89th Division – Maj Gen William M. Wright
  • 135th Aero Squadron
  • 43rd Balloon Company
  • 42nd Division – Maj Gen Charles T. Menoher
  • 90th Aero Squadron
  • 3rd Balloon Company
  • 1st Division – Maj Gen Charles Pelot Summerall
  • 8th Aero Squadron
  • 9th Balloon Company
  • 3rd Division (Corps Reserve) – Maj Gen Beaumont B. Buck
  • V Corps – Maj Gen George H. Cameron
  • Headquarters Observation Group
  • 99th Aero Squadron
  • 7th Balloon Company
  • 26th Division – Maj Gen Clarence Ransom Edwards
  • 88th Aero Squadron
  • 104th Aero Squadron
  • 6th Balloon Company
  • 15th Colonial Division (French)
  • 8th Balloon Company
  • 4th Division – Maj Gen John L. Hines
  • 8th Brigade
  • 4th Field Artillery Brigade
  • remainder of Division in reserve
  • 12th Balloon Company
  • US Army Reserve
  • 35th Division – Maj Gen Peter E. Traub
  • 80th Division – Maj Gen Adelbert Cronkhite
  • 91st Division – Maj Gen William H. Johnston
  • 2d Pursuit Group under First U.S. Army command
  • 13th Aero Squadron

Order of Battle, French Army, 12 September 1918

  • (2e CAC) - Gen Ernest Joseph Blondlat
  • 2e division de cavalerie à pied (2e DCP) - Gen Hennocque
  • 26e division d'infanterie - Gen de Belenet
  • 39e division d'infanterie - Gen Pougin
  • Division Aérienne (France) – Gen Duval
  • 1st Air Brigade
  • 2nd Air Brigade

Aftermath

One reason for the American forces' success at St. Mihiel was General Pershing's thoroughly detailed operations order. Pershing's operation included detailed plans for penetrating the Germans' trenches, using a combined arms approach to warfare.