It was stationed in Kobryn, as well as other towns of the Polesie Voivodeship - Brześć nad Bugiem and Pinsk.
In the Polish September Campaign, the division, under General Leopold Cehak, was part of the Operational Group "Piotrków" of the Łódź Army.
The 30th was the only division of the Polish Army, which took its defensive positions near pre-1939 Polish-German border as early as in March 1939.
On September 2, 1939, the Wehrmacht broke through Polish lines and crossed the Warta near Działoszyn, street fighting took place in the very town.
On the same day in the evening, the Germans organized a general attack, forcing the Poles to withdraw towards its main defence line, along the Widawka river.