AK) in script to avoid confusion with the Roman numerals, was formed under the name Generalkommando Y on 2 August 1942 in occupied France.

[4] By early June 1944, as Allied troops were about to land in Normandy, the corps headquarters were still at Antwerp, and its subordinate 48th, 712th and 165th Infantry Divisions were stationed at Ostende, Oostburg and Middelburg, respectively.

The LXXXIX Army Corps was tasked with the defense of the Moselle from Koblenz over Wierschem to a sector north of Cochem.

[11] The corps was insufficiently equipped to defend the serpentine mountainous Moselle area, as it lacked both the manpower required to defend the north bank as well as the reserves required to beat back Allied attempts to cross the Moselle.

[12] The remainders of the depleted 6th SS Mountain Division began joining the LXXXIX Army Corps piecemeal on the morning of 15 March 1945, whereupon they were sent by Höhne against the left flank of the U.S. 90th Infantry Division in a futile attempt to push back against the Moselle bridgehead established by XII Corps and to hold open a retreat route towards the Rhine river.

The troops that arrived on the east bank of the Rhine as part of the retreat by LXXXIX Army Corps numbered around 1,700.

[16] They were helped in their retreat by a lack of American activity; the 4th Armored Division (Gaffey), part of XII Corps, had paused to regroup after establishing a bridgehead across the Nahe river.

[17] By 25 March 1945, the 6th SS Mountain Division had been called away by Albert Kesselring, the commanding general of Army Group D and thus Supreme Commander of the Wehrmacht forces in the West, towards Wiesbaden, weakening the defensive position of LXXXIX Army Corps east of the Rhine even further,[18] just before the U.S. VIII Corps (Middleton) crossed the Rhine Gorge into the sector defended by LXXXIX Army Corps.

Kesselring reverted his decision after news arrived of the American advances, and attempted to engage the 6th SS Mountain Division to defend the Lahn river in the Limburg area, but the 6th SS Mountain Division was out of fuel, and its troops, now marching on foot, came too late to prevent Limburg's capture by American troops on 26 March.

[20] Faced with the VIII Corps in the west and threatened by the American breakthrough at Limburg, Höhne, at last in contact with Kesselring, requested the right to retreat his battered forces towards the east, but was denied.

[21] In the meantime, the remainders of the 6th SS Mountain Division, numbering some 2,000 troops, took to setting up roadblocks on the motorways they attempted to defend, in spite of the fact that several American contingents had already passed them by on either side.