Polish 19th Infantry Division was formed in 1923, from three regiments of the divisions that had previously formed armed forces of the Republic of Central Lithuania. Originally, it consisted of the following infantry regiments:
During the interbellum period, the division was stationed in the city of Wilno, which in 1922–1939 was part of the Second Polish Republic. Until 1927, it was commanded by General Michal Tokarzewski-Karaszewicz, who was replaced by General Tadeusz Kasprzycki (1927–1931). For most of the 1930s, the division was commanded by General Eugeniusz Godziejewski, who in mid-April 1936 was replaced by its last interbellum commandant, General Jozef Kwaciszewski. The 19th I.D. fought in the September 1939 German Invasion of Poland, as part of the Prusy Army. Later it was recreated as a Home Army unit, taking part in the Operation Ostra Brama in the summer of 1944.
The 19th I.D. under General Jozef Kwaciszewski belonged to northern group of Prusy Army, under General Stefan Dąb-Biernacki. On September 5, 1939, the division was sent to the area of Piotrków Trybunalski, where it faced the 1st Panzer Division of the Wehrmacht. Under German pressure, it had to withdraw on September 6, and on the same day, the Germans captured General Kwaciszewski. On September 7 in the evening, units of the division scattered, trying to break through German lines and escape eastwards, towards the Vistula.
On September 8 Colonel Tadeusz Pelczynski began reconstruction of the division, with two infantry regiments (77th, 86th), and some artillery, which managed to cross the Vistula. Following the order of General Dab-Biernacki, its name was changed to the 19th Infantry Brigade. The unit took part in the Battle of Tomaszów Lubelski, capitulating on September 27.