Infanterie-Division) was an infantry division that notably served in World War II as part of the Heer of Nazi Germany's Wehrmacht.

The staff of the 1st Infantry Division was initially assembled under the cover name of Artillery Leader 1 (German: Artillerieführer I) in October 1934.

[3] On 23 March 1939, after a German ultimatum of three days prior regarding the status of the Memelland, occupied since 1923 by Lithuania, had been accepted by the Lithuanian government and a treaty signed by Joachim von Ribbentrop and Juozas Urbšys, soldiers of the 1st Infantry Division moved from their East Prussian barracks into the city of Memel (Lithuanian: Klaipėda), thus participating in the reintegration of that city and its region into Germany.

On 17 August 1939, the 1st Infantry Division initiated mobilization procedures as part of the German preparations for the Invasion of Poland.[1]: 20f.

The division's commanding general was Joachim von Kortzfleisch, while the chief of staff and head of logistics were Major Johannes Steffler and Captain Christian Müller.

[6]: 31  On the 12th, the 1st Infantry Division reached the road between Kałuszyn and Siedlce, where it was engaged by Polish counterattacks on its left flank.

[6]: 67  It advanced to Łochów two days later;[6]: 69  on 25 September it was northwest of Ostrów Mazowiecka as its army corps was preparing to withdraw behind the Narew river.

[7]: 181 In September 1940, the 1st Infantry Division was shuffled out of German-occupied France and sent back to its home region, East Prussia.[1]: 20f.

[8]: 183  On 17 July, it stood in heavy fighting east of Lake Peipus, making only slow stepwise progress towards Gdov.

[3] Alternating between 3rd Panzer and 4th Armies, the division was trapped in the Königsberg/Samland area after it was cut off from the rest of Germany by end January 1945.

At 0400 hours on 19 February 1945, elements of the 1st Infantry, led by a captured Soviet T-34 tank, spearheaded a westward offensive from Königsberg intended to link with General Hans Gollnick's XXVIII Corps, which held parts of the Samland peninsula, including the vital port of Pillau.

This action re-opened the land route from Königsberg to Pillau, allowing for the evacuation of civilian refugees via the port and solidifying the German defense of the area until April.

The final divisional commander was a colonel-ranked officer named Egon Overbeck, who assumed the post on 26 April 1945, after Henning von Thadden had been wounded in action.