The First United States Army launches its first offensive on September 12, 1918 against the salient of St. Mihiel. The attack force consisted of three US corps and a French corps. By the time the battle ended on September 15, the Allies had captured the salient and inflicted 22,500 casualties on the Germans while sustaining 7,000 casualties. Here is General Pershing’s report on the battle:
At the first operation of the American army the reduction of the salient of St. Mihiel was to he undertaken as soon as the necessary troops and material could be made available. On account of the swampy nature of the country it was especially important that the movement be undertaken and finished before the fall rains should begin, which was usually about the middle of September.
Arrangements were concluded for successive relief of American divisions, and the organization of the First American Army under my personal command was announced on August 10th, with La Fertesous-Jouarre as headquarters. This army nominally assumed control of a portion of the Vesle front, although at the same time directions were given for its secret concentration in the St. Mihiel sector.
The force of American soldiers in France at that moment was sufficient to carry out this offensive, but they were dispersed along the front from Switzerland to the Channel.
The three Army Corps headquarters to participate in the St. Mihiel attack were the First, Fourth, and Fifth. The First was on the Vesle, the Fourth at Toul, and the Fifth not yet completely organized. To assemble combat divisions and service troops and undertake a major operation, within the short period available and with staffs so recently organized, was an extremely difficult task.
Our deficiencies in artillery, aviation, and special troops, caused by the shipment of an undue proportion of infantry and machine guns during the summer, were largely met by the French.
The reduction of the St. Mihiel salient was important, as it would prevent the enemy from interrupting traffic on the Paris-Nancy Railroad by artillery fire and would free the railroad leading north through St. Mihiel to Verdun. It would also provide us with an advantageous base of departure for an attack against the Metz-Sedan Railroad system which was vital to the German armies west of Verdun, and against the Briey Iron Basin which was necessary for the production of German armament and munitions.
The general plan was to make simultaneous attacks against the flanks of the salient. The ultimate objective was tentatively fixed as the general line Marieulles (east of the Moselle) – heights south of Gorze-Mars la Tour-Etain.
The operation contemplated the use on the western face of 3 or 4 American divisions, supported by the attack of 6 divisions of the Second French Army on their left, while 7 American divisions would attack on the southern face, and 3 French divisions would press the enemy at the tip of the salient. As the part to be taken by the Second French Army would be closely related to the attack of the First American Army, Gen. Petain placed all the French troops involved under my personal command.
By August 30th, the concentration of the scattered divisions, corps, and army troops, of the quantities of supplies and munitions required, and the necessary construction of light railways and roads, were well under way.
In accordance with the previous general consideration of operations at Bombon on July 24th, an Allied offensive extending practically along the entire active front was eventually to be carried out. After the reduction of the St. Mihiel sector the Americans were to cooperate in the concerted effort of the Allied armies.
It was the sense of the conference of July 24th, that the extent to which the different operations already planned might carry us could not be then foreseen, especially if the results expected were achieved before the season was far advanced. It seemed reasonable at that time to look forward to a combined offensive for the autumn, which would give no respite to the enemy and would increase our advantage for the inauguration of succeeding operations extending into 1919.
On August 30th, a further discussion with Marshal Foch was held at my headquarters at Ligny-en-Barrois. In view of the new successes of the French and British near Amiens and the continued favourable results toward the Chen in des Dawes on the French front, it was now believed that the limited Allied offensive, which was to prepare for the campaign of 1919, might be carried further before the end of the year.
At this meeting it was proposed by Marshal Foch that the general operations as far as the American Army was concerned should be carried out in detail by:
(a) An attack between the Meuse and the Argonne by the Second French Army, reinforced by from four to six American divisions.
(b) A French-American attack, extending from the Argonne west to the Souain Road, to be executed on the right by an American Army astride the Aisne and on the left by the Fourth French Army.
To carry out these attacks the 10 to 11 American divisions suggested for the St. Mihiel operation and the 4 to 6 for the Second French Army, would leave 8 to 10 divisions for an American Army on the Aisne. It was proposed that the St. Mihiel operation should he initiated on September 10th and the other two on September 15th and 20th, respectively.
The plan suggested for the American participation in these operations was not acceptable to me because it would require the immediate separation of the recently formed First American Army into several groups, mainly to assist French armies. This was directly contrary to the principle of forming a distinct American Army, for which my contention had been insistent.
An enormous amount of preparation had already been made in construction of roads, rail-roads, regulating stations, and other installations looking to the use and supply of our armies on a particular front. The inherent disinclination of our troops to serve under Allied commanders would have grown and American morale would have suffered.
My position was stated quite clearly that the strategical employment of the First Army as a unit would be undertaken where desired, but its disruption to carry out these proposals would not be entertained.
A further conference at Marshal Foch’s headquarters was held on September 2nd, at which Gen. Petain was present. After discussion the question of employing the American Army as a unit was conceded. The essentials of the strategical decision previously arrived at provided that the advantageous situation of the Allies should be exploited to the utmost by vigorously continuing the general battle and extending it eastward to the Meuse.
All the Allied armies were to be employed in a converging action. The British armies, supported by the left of the French armies, were to pursue the attack in the direction of Cambrai; the centre of the French armies, west of Rheims, would continue the actions, already begun, to drive the enemy beyond the Aisne; and the American Army, supported by the right of the French armies, would direct its attack on Sedan and Mezieres.
It should be recorded that although this general offensive was fully outlined at the conference no one present expressed the opinion that the final victory could be won in 1918. In fact, it was believed by the French high command that the Meuse-Argonne attack could not be pushed much beyond Montfaucon before the arrival of winter would force a cessation of operations.
The choice between the two sectors, that east of the Aisne including the Argonne Forest, or the Champagne sector, was left to me. In my opinion, no other Allied troops had the morale or the offensive spirit to overcome successfully the difficulties to be met in the Meuse-Argonne sector and our plans and installations had been prepared for an expansion of operations in that direction.
So the Meuse-Argonne front was chosen. The entire sector of 150 kilometres of front, extending from Port-sur-Seille, east of the Moselle, west to include the Argonne Forest, was accordingly placed under my command, including all French divisions then in that zone.
The First American Army was to proceed with the St. Mihiel operation, after which the operation between the Meuse and the western edge of the Argonne Forest was to be prepared and launched not later than September 25th.
As a result of these decisions, the depth of the St. Mihiel operation was limited to the line Vigneulles-Thiaucourt-Regnieville. The number of divisions to be used was reduced and the time shortened. Eighteen to 19 divisions were to be in the front line. There were 4 French and 15 American divisions available, 6 of which would be in reserve, while the two flank divisions of the front line were not to advance.
Furthermore, 2 Army Corps headquarters, with their corps troops, practically all the Army Artillery and Aviation, and the First, Second, and Fourth Divisions, the first two destined to take a leading part in the St. Mihiel attack, were all due to be withdrawn and started for the Meuse-Argonne by the fourth day of the battle.
The salient had been held by the Germans since September, 1914. It covered the most sensitive section of the enemy’s position on the Western Front; namely, the Mezieres-Sedan-Metz Railroad and the Briey Iron Basin; it threatened the entire region between Verdun and Nancy, and interrupted the main rail line from Paris to the east.
Its primary strength lay in the natural defensive features of the terrain itself. The western face of the salient extended along the rugged, heavily wooded eastern heights of the Meuse; the southern face followed the heights of the Meuse for 8 kilometres to the east and then crossed the plain of the Woevre, including within the German lines the detached heights of Loupmont and Montsec which dominated the plain and afforded the enemy unusual facilities for observation.
The enemy had reinforced the positions by every artificial means during a period of four years.
On the night of September 11th, the troops of the First Army were deployed in position. On the southern face of the salient was the First Corps, Maj. Gen. Liggett, commanding, with the Eighty-second, Ninetieth, Fifth, and Second Divisions in line, extending from the Moselle westward.
On its left was the Fourth Corps, Maj. Gen. Joseph T. Dick-man, commanding, with the Eighty-ninth, Forty-second, and First Divisions, the left of this corps being opposite Montsec. These two Army Corps were to deliver the principal attack, the line pivoting on the centre division of the First Corps.
The First Division on the left of the Fourth Corps was charged with the double mission of covering its own flank while advancing some 20 kilometres due north toward the heart of the salient, where it was to make contact with the troops of the Fifth Corps.
On the western face of the salient lay the Fifth Corps, Maj. Gen. George H. Cameron, commanding, with the Twenty-sixth Division, Fifteenth French Colonial Division, and the Fourth Division in line, from Mouilly west to Les Eparges and north to Watronville.
Of these three divisions, the Twenty-sixth alone was to make a deep advance directed southeast toward Vigneulles. The French Division was to make a short progression to the edge of the heights in order to cover the left of the Twenty-sixth. The Fourth Division was not to advance.
In the centre, between our Fourth and Fifth Army Corps, was the Second French Colonial Corps, Maj. Gen. E. J. Blondlat, commanding, covering a front of 40 kilometres with 3 small French divisions. These troops were to follow up the retirement of the enemy from the tip of the salient.
The French independent air force was at my disposal which, together with the British bombing squadrons and our own air forces, gave us the largest assembly of aviation that had ever been engaged in one operation. Our heavy guns were able to reach Metz and to interfere seriously with German rail movements.
At dawn on September 12th, after four hours of violent artillery fire of preparation, and accompanied by small tanks, the Infantry of the First and Fourth Corps advanced. The infantry of the Fifth Corps commenced its advance at 5 a.m.
The operation was carried out with entire precision. Just after daylight on September 13th, elements of the First and Twenty-sixth Divisions made a junction near Hattonchatel and Vigneulles, 18 kilometres northeast of St. Mihiel.
The rapidity with which our divisions advanced overwhelmed the enemy, and all objectives were reached by the afternoon of September 13th. The enemy had apparently started to withdraw some of his troops from the tip of the salient on the eve of our attack, but had been unable to carry it through.
We captured nearly 16,000 prisoners, 443 guns, and large stores of material and supplies. The energy and swiftness with which the operation was carried out enabled us to smother opposition to such an extent that we suffered less than 7,000 casualties during the actual period of the advance.
During the next two days the right of our line west of the Moselle River was advanced beyond the objectives laid down in the original orders. This completed the operation for the time being and the line was stabilized to be held by the smallest practicable force.
The material results of the victory achieved were very important. An American army was an accomplished fact, and the enemy had felt its power. No form of propaganda could overcome the depressing effect on the morale of the enemy of this demonstration of our ability to organize a large American force and drive it successfully through his defences.
It gave our troops implicit confidence in their superiority and raised their morale to the highest pitch. For the first time wire entanglements ceased to be regarded as impassable barriers and open-warfare training, which had been so urgently insisted upon, proved to be the correct doctrine.
Our divisions concluded the attack with such small losses and in such high spirits that without the usual rest they were immediately available for employment in heavy fighting in a new theatre of operations.
The strength of the First Army in this battle totalled approximately 500,000 men, of whom about 70,000 were French.