The Third United States Army was first activated during the First World War on 7 November 1918, at
Chaumont, France, when the General Headquarters of the
American Expeditionary Forces (AEF) issued General Order 198 organizing the Third Army and announcing its headquarters staff. On the 15th, four days after the
Armistice with Germany, Major General
Joseph T. Dickman assumed command and issued Third Army General Order No. 1. The Third Army consisted of three corps (
III Corps, Major General
John L. Hines;
IV Corps, Major General
Charles Henry Muir; and
VII Corps, Major General
William G. Haan) and seven divisions.
First mission On 15 November 1918, Major General Dickman was given the mission to move quickly and by any means into the
Rhineland on occupation duties. He was to disarm and disband German forces as ordered by General
John J. Pershing, commander of the AEF. The march into the Rhineland for occupation duty was begun on 17 November 1918. By 15 December the Third Army Headquarters at
Mayen opened at
Koblenz. Two days later, on 17 December 1918, the Koblenz bridgehead, consisting of a pontoon bridge and three railroad bridges across the Rhine, had been established. Third Army troops had encountered no hostile act of any sort. In the occupied area, both food and coal supplies were sufficient. The crossing of the Rhine by the front line divisions was effected in good time and without confusion. Troops, upon crossing the Rhine and reaching their assigned areas, were billeted preparatory to occupying selected positions for defense. The strength of the Third Army as of 19 December, the date the bridgehead occupation was completed, was 9,638 officers and 221,070 enlisted men.
Third Army advance in
Cochem, Germany, was home to the
IV Corps, Third Army, in 1919. On 12 December, Field Order No. 11 issued, directed the Third Army to occupy the northern sector of the Coblenz bridgehead, with the advance elements to cross the
Rhine river at seven o'clock, 13 December. The northern (left) boundary remained unchanged. The southern (right) boundary was as has been previously mentioned. Before the advance, the 1st Division passed to the command of the III Corps. With three divisions, the 1st, 2d, and 32d, the III Corps occupied the American sector of the Coblenz bridgehead, the movement of the troops into position beginning at the scheduled hour, 13 December. The four bridges available for crossing the river within the Coblenz bridgehead were the pontoon bridge and railroad bridge at Coblenz, the railroad bridges at
Engers and
Remagen. On 13 December the advance began with the American khaki crossing the Rhine into advanced positions. On the same day the
42d Division passed to the command of the
IV Corps, which, in support of the III Corps, continued its march to occupy the
Kreise of
Mayen,
Ahrweiler,
Adenau, and
Cochem. The VII Corps occupied under the same order that portion of the
Regierungsbezirk of
Trier within army limits. On 15 December, Third Army Headquarters at
Mayen opened at Coblenz: III Corps Headquarters at Polch opened at Neuwied and IV Corps Headquarters remained at Cochem, with the VII Corps at
Grevenmacher. In crossing the Rhine on the shortened front—from
Rolandseck to
Rhens on the west bank—the Third Army encountered no hostile act of any sort. In the occupied area both food and coal supplies were sufficient. By the night of 14 December, Third Army troops had occupied their positions on the perimeter of the Coblenz bridgehead.
Army of Occupation During January 1919, the Third Army was engaged in training and preparing the troops under its command for any contingency. A letter of instruction was circulated to lower commanders prescribing a plan of action in case hostilities were resumed. Installations were set up throughout the Army area to facilitate command. In February, military schools were opened through the Third Army area; a quartermaster depot was organized; 2,000 officers and enlisted men left to take courses in British and French universities; better leave facilities were created; and plans for sending American divisions to the United States were made. On 4 February, the military control of the Stadtkreis of Trier was transferred from GHQ to the Third Army. In March, routine duties of occupation and training were carried on; an Army
horse show was held; Army, corps, and divisional educational centers were established in the Third Army Zone; the Coblenz port commander took over the duties of the Coblenz regulating officer; and the 42d Division was released from IV Corps and was placed in Army Reserve. In April, the exodus of American divisions from Third Army to the United States began. During the month, motor transport parks were established; an Army
motor show was held; the Army area was reorganized; and the centralization of military property was initiated in anticipation of returning it to the United States. On 20 April 1919, Third Army command changed from Maj. Gen. Dickman to Lt. Gen.
Hunter Liggett.
Preparations to advance On 14 May 1919, Marshal
Ferdinand Foch, General-in-Chief of the Allied Armies, submitted plans of operations to the Third Army commander to be used in the event that Germany should refuse to sign the peace treaty. On 20 May, Marshal Foch directed allied commanders to dispatch troops toward
Weimar and Berlin in the event the peace treaty was not signed. On 22 May, the Third Army issued its plan of advance, effective 30 May, in view of the impending emergency. On 27 May, Foch informed Pershing that the Supreme War Council desired that allied armies be made ready immediately to resume active operations against the Germans. On 1 June, the advance GHQ, AEF, at Trier was discontinued. On 16 June, Foch notified Pershing that the allied armies must be ready after 20 June to resume offensive operations, and that preliminary movements were to begin 17 June. On 19 June, Pershing notified Foch that beginning 23 June, the Third Army would occupy the towns of Limburg, Westerburg, Hachenburg, and Altenkirchen, and that III Corps would seize the railroad connecting these towns. On 23 June, the Germans signified their intention to sign the peace treaty, and the contemplated military operations were suspended. On 30 June, Foch and Pershing conferred about the American troops to be left on the Rhine.
A separate peace On 1 July, General Pershing notified the War Department that upon Germany's compliance with military conditions imposed upon her (probably within three months after German ratification of the treaty), the American forces in Europe would be reduced to a single regiment of infantry supplemented by necessary auxiliaries. Accordingly, the Third Army was disbanded on 2 July 1919. Its headquarters and all personnel (numbering about 6,800 men) and units under it were thereafter designated American Forces in Germany. This force would remain in Germany, as part of the
Occupation of the Rhineland, for over three years. This was due, at least in part, to the fact that the United States, having rejected the Treaty of Versailles, was therefore still "
de jure" at war with Germany. This situation remained unresolved until the summer of 1921 when a separate
peace treaty was signed. ==Reactivation and the interwar period==