In the interbellum period, the headquarters of the division was stationed in Zamość, while its regiments were garrisoned in Chelm, Lublin, Zamosc and other locations.
Since divisional headquarters was still on the way to the concentration point, these battalions were temporarily commanded by General Gustaw Paszkiewicz of the 12th Infantry Division.
Since German armoured forces succeeded in breaking Polish positions and quickly advanced, General Stanislaw Skwarczynski ordered all units to withdraw behind the Vistula river.
On September 6, the Germans captured Ostrowiec Swietokrzyski, and two days later, Skarzysko-Kamienna, advancing then towards Szydlowiec in an attempt to divide the Poles into two groups.
On September 9, a regiment of German tanks surprised the headquarters of the 3rd Legions Division, which at that time was located south of the village of Seredzice.
To disorient the enemy, 8th Legions Regiment carried out a successful attack on German positions at Trebowiec Duzy.
In the evening of September 9, commandant of the 3rd Legions Division formed an assault group, tasked with opening the route for the retreating units.
The attack began at 2030, but Polish soldiers were immediately sprayed by machine gun fire from German positions on the local hills.
Nevertheless, the Poles advanced, reaching the headquarters of German 9th Motorized Infantry Regiment, whose commandant was killed in battle.
After the clash, elements of the 3rd Legions Division were ordered to try to break through German positions and reach Solec nad Wisla.
Those who managed to cross the Vistula joined 1st Legions Infantry Division, and fought in the Battle of Tomaszow Lubelski.
Other soldiers joined the unit of Colonel Stanislaw Gumowski, which was part of Polish Northern Front (1939), and fought near Krasnystaw.