Stationed in Łomża and commanded in 1939 by Colonel Stefan Kossecki, it was part of the Narew Independent Operational Group.

Dywizja Zmechanizowana) as part of an expansion of the Polish Army, partially as a result of heightened security threats to Poland.

Between 1919 and 1939, Łomża and neighboring towns were located very close to the border of Poland and German province of East Prussia.

The efforts of Polish soldiers were mixed, but on the night of Sept 9-10, it attacked a German armored column, destroying several vehicles and tanks.

During the next days the Division was engaged in heavy fights with units of General Heinz Guderian's XIX Army Corps.