U.S. Joint Operations Plan for Operation Overlord

▪ Primary Source

      Headquarters First U.S. Army Group

      Like the plan for establishing the Normandy lodgment area (First U.S. Army Operations Plan “Neptune”), the Joint Operations Plan for Operation Overlord is concerned with the broad objectives and missions of U.S. ground, air, and naval forces. However, because its prime concern is the extension of the campaign beyond Normandy, this document gives special prominence to Courtney Hodges (Hodges, Courtney Hicks)'s First Army (which was to cut off the Brittany peninsula and turn east toward Paris), George Patton (Patton, George Smith)'s Third Army (which was to form the spearhead of the thrust through Brittany and then eastward), J.C.H. Lee (Lee, John Clifford Hodges)'s ETOUSA (European Theater of Operations, United States Army; the logistics branch), and the troops of “Com Z” (the Communications Zone; to be established immediately behind the advancing armies).

      This document refers to the First United States Army Group (FUSAG). FUSAG existed as a headquarters only; once the breakout from Normandy actually took place, U.S. ground forces were placed under the umbrella of Omar Bradley (Bradley, Omar Nelson)'s Twelfth Army Group.

      SECTION I

      SITUATION

      . . . 2. General Information.

      a.The object of Operation OVERLORD (Outline Plan, C.O.S. (43) 416 (O)) is to secure a lodgement area on the Continent from which further offensive operations can be developed. The operation will be executed in two phases:

      Phase I - The assault and capture of an initial lodgement area including the development of airfield sites in the CAEN area and the capture of CHERBOURG.

      Phase II - Enlargement of the lodgement area to include the BRITTANY PENINSULA, all ports south to the LOIRE, and the area between the LOIRE and the SEINE.

      Phase I and some parts of Phase II will be executed by U.S., British and Canadian forces assigned or attached to the 21 Army Group.

      b. At a time to be designated by SHAEF, the First U.S. Army Group, as such, will take over certain areas, missions, and the U.S. Forces then under 21 Army Group. SHAEF and 21 Army Group directives have also charged FUSAG with coordinating, under the direction of 21 Army Group, the planning of U.S. Forces (less First U.S. Army and its accompanying forces) for all action following the arrival of First U.S. Army on the Continent.

      3. Object.

      This Joint Plan will prescribe the responsibilities of the major U.S. Forces following First U.S. Army, and provide a common basis for further detailed planning, under FUSAG coordination, by the respective Forces and their subordinate echelons. Until Third Army is operating there, this Plan is concerned only with the movement to the Continent of U.S. Forces which follow the last organic corps of the First Army. It is estimated that this movement will start on D + 15. . . .

      5. Allied Forces.

      At the end of Phase I Allied Forces are assumed to have reached the line shown on Map A of Annex 1 as D + 20. Ninth Air Force is estimated to have eleven fighter groups operating from fields on the Continent. First U.S. Army has three corps abreast, generally along the line AVRANCHES-DOMFRONT. The port of CHERBOURG is open and in operation under U.S. control. British, Canadian and U.S. heavy supplies are being processed through this port but the bulk of all supplies are still coming over the beaches. No other major port has been opened.

      SECTION II

      MISSIONS AND ORGANIZATION

      6. Missions.

      a.Joint Missions. Third Army, Ninth Air Force, Navy and Fwd Ech Com Z, being mounted by ETOUSA and coordinated by FUSAG, will jointly prepare to move the remaining elements of their respective forces to the Continent, in order to capture and develop the BRITTANY PENINSULA for the maintenance of U.S. Forces, and thereafter to conduct further operations on the Continent within an area to be allotted by SHAEF to FUSAG.

      b. FUSAG Mission. Under the supervision of 21 Army Group FUSAG will coordinate the movement of Third Army, Ninth Air Force and Com Z troops and U.S. Naval personnel as a continuation of the First Army movement and will plan for operations in two stages as follows:

      STAGE I - Commence occupation of the BRITTANY PENINSULA and open any essential minor ports thereon. Develop QUIBERON BAY Area as a major port of entry as soon as secured. Complete the organization of the Com Z throughout the COTENTIN PENINSULA and commence its organization in the BRITTANY PENINSULA.

      STAGE II - Concentrate the Third Army north of the LOIRE facing east. Complete the reduction of the BRITTANY PENINSULA and its organization as a part of the COM Z.

      c. Ninth Air Force Mission. The Ninth Air Force will complete the movement of its remaining elements to the Continent, coordinated with movement of ground forces, and will continue the development of airfields and the execution of air operations in the U.S. sector as directed by AEAF.

      d. Naval Mission.

      (1) The Western Naval Task Force will transport ground and Air Force elements to the Continent and furnish Naval fire support for attacks by land and air forces in coastal areas as required. It will also assist in the rehabilitation and restoration of captured ports and port facilities. . . .

      (3) The prevention of enemy reinforcement of the BRITTANY PENINSULA across its Atlantic Coastal perimeter is a responsibility of the Admiralty.

      e. ETOUSA Mission. Mounting of all U.S. Forces moving from the UK (including NI [Northern Ireland]) for operation OVERLORD is the responsibility of ETOUSA. . . . The Mounting Plan is inherently flexible to the extent that there is always in the concentration area a 10 days' reserve of units preparing to embark. Any of these units can be embarked within 3 days after they have been requested. In addition one division and certain critical troops from well down on the priority list will be held in a concentration area ready for immediate shipment after D + 20. . . .

      SECTION III

      OPERATIONS

      9. Ground Forces.

      a. First Army, including: four corps headquarters (three organic and one attached from Third Army upon arrival on the Continent); nine infantry divisions (including three divisions from Third Army, two of which will be attached upon arrival on the Continent); two armored divisions; two airborne divisions (to return to UK about D + 15 for refitting).

      STAGE I - After capturing CHERBOURG, the First Army will drive to the south and southeast to cut off the BRITTANY PENINSULA, secure the QUIBERON BAY area, to include BELLE ISLE and such other small islands as are necessary for the control of the QUIBERON BAY area, and establish the southern limit of the lodgement area along the lower LOIRE. The First Army will then undertake to clean up resistance on the BRITTANY PENINSULA. VIII Corps will revert to command of Third Army when Third Army Headquarters becomes operational on the Continent. Necessary supporting troops for VIII Corps will be attached from First Army until such time as Third Army troops become available. If the First Army has not captured the QUIBERON BAY area and BELLE ISLE by the time Headquarters Third Army becomes operational on the Continent, First Army will be prepared to attach to the Third Army two ranger battalions or one amphibiously trained RCT [Regimental Combat Team] together with such airborne troops as are required for this operation.

      STAGE II - First Army will advance to the line of the UPPER SEINE prepared for further action to the northeast, and assume command of the British Corps southwest of PARIS.

      b. Third Army, including: three corps headquarters (in addition to one attached to First Army); five infantry divisions (in addition to three attached to First Army); four armored divisions; one French armored division.

      STAGE I - (1) Third Army, less VIII Corps, will land on the Continent, as soon as possible after First Army, in one or more of the following ways:

      (a) Through CHERBOURG, or over the beaches between VARREVILLE (4299) and COLLEVILLE-SUR-MER (6888) and the beaches and minor ports north and east of ST. MALO (incl.). This may be the quickest method of bringing in Third Army, or elements thereof.

      (b) Through the BRITTANY ports or beach installations as they become available, particularly those in the QUIBERON BAY area.

      (c) If no ports or beach installations can be secured in the BRITTANY PENINSULA by land operations or if undue delay is incurred in their capture, it may become necessary or desirable to adopt the alternative plan referred to in paragraph 12 below.

      (2) When Third Army Headquarters becomes operational on the Continent, they will resume command of the VIII Corps and operating on the right of the First Army, will complete such parts of the following missions as have not been accomplished by First Army:

      (a) Capture the QUIBERON BAY Area.

      (b) Capture BELLE ISLE, and such other small islands as are necessary for the control of the QUIBERON BAY Area. For this operation Third Army will utilize certain units provided by the First Army, namely: two ranger battalions or one RCT (amphibious) and necessary airborne troops.

      (c) Complete the capture of the BRITTANY PENINSULA and open the remainder of the BRITTANY Ports.

      STAGE II - After clearing the BRITTANY PENINSULA, Third Army will concentrate on the right of the First Army, prepared to operate to the east, either in close conjunction with the First Army, or by swinging south of the LOIRE if a wider envelopment is feasible. It will place one armored division in FUSAG reserve near LE MANS.

      c. Com Z Troops.

      STAGE I - Advance Section Com Z will complete the organization of the COTENTIN PENINSULA including the port of CHERBOURG as part of the Com Z. Fwd Ech Com Z will then begin to open and develop ports on the BRITTANY PENINSULA giving the QUIBERON BAY area first priority.

      STAGE II - Fwd Ech Com Z will complete the opening and development of BRITTANY Ports including QUIBERON BAY, BREST and such other ports as are necessary. It will take over the BRITTANY PENINSULA from Third Army for organization as part of the Com Z, which will extend eastward to include LE MANS. . . .

      10. Naval Forces.

      a. The craft and ships used in the build-up of the First Army will continue in the cross-channel service and be used to transport the remaining units of the First Army Group and associated elements from the UK to the beaches and ports in Northwest France.

      b. WNTF [Western Naval Task Force] will be prepared to furnish the necessary naval support and lift for one RCT (amphibious) or at least two ranger battalions for the capture of BELLE ISLE.

      11. Ninth Air Force.

      a. The Ninth Air Force will be associated with the First Army Group. The Ninth Air Force will be employed as a Tactical Air Force in support of the ground forces as directed by Joint Ninth Air Force and 2nd TAF (RAF) Commanders in coordination with AEAF. Request from the ground forces for air support will normally be made thru an Air Support Commander or his representative.

      (1) Tactical Air Support will be accomplished by:

      (a) Gaining the necessary degree of air superiority.

      (b) Preventing the movement of hostile troops and supplies into the theater of operations.

      (c) Participation in a combined effort of the air and ground forces, in the battle area, to gain objectives on the immediate front of the ground forces.

      b. In the UK the Air Commander is the Commanding General, Ninth Air Force. On the Continent, the Air Commander will be the Senior Air Officer of the Ninth Air Force present until such time as the Commanding General, Ninth Air Force arrives. . . .

      e. At each corps and division headquarters there will be an air support party, consisting of one air support officer, with radio and wire communication facilities and enlisted personnel for their operation. The radio facilities will include HF for reporting back to Tactical Air Command, and VHF for talking to airplanes in the air. The Air Support Officer acts in an advisory and liaison capacity with the operating staff of the division or corps. It is his duty to pass back to the Joint Army / Tactical Air Command Headquarters all approved requests for air support, tactical and photographic reconnaissance, location of bomb line, local weather data, and all pertinent information to which he has access. Support requests from division may be monitored by corps. . . .

      h. The capture of areas that contain airfield sites is a vital objective. This responsibility must be impressed upon all commanders down to and including those of RCTs. The speed with which airfield sites can be made operational, directly affects the speed with which air support can be made available to the ground forces. . . .

      12. Alternative Plan.

      It may develop that the First U.S. Army, after having cut off the BRITANNY PENINSULA, will, with a part of the Third Army, be contained and be unable to secure either BREST or the QUIBERON BAY area without undue delay. If maintenance of additional troops through ports and beaches already secured is impossible, one or more additional major ports will have to be taken to permit further development of the lodgement area. A plan to expedite this phase of the operations is being considered under the code name of SWORDHILT. Further instructions on this subject will be issued. . . .

      15. Resistance Groups.

      Resistance Groups will put into effect throughout FRANCE and BELGIUM certain pre-arranged plans, including particularly attacks on enemy rail, road, and telecommunications. In addition, Resistance Groups will be called upon to perform missions in strategic rear areas designed to interfere with the enemy's moves to oppose the advance of the Allied armies. Small, specially trained and equipped military units will be prepared to operate with resistance elements behind the enemy's lines so as to carry out specific harassing and destructive missions. For SOE/SO Plan, see Annex [Annex 25 of Operations Plan "Neptune"].

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