37 Leczycki Infantry Regiment - formed in late 1918.
A little bit of translation from Wiki page about this regiment:
In his tradition 37th Infantry Regiment alluded to Duchy of Warsaw 4th Fusiliers Regiment. In the Polish-Ukrainian war he fought to open the way to the Lviv defender's taking Grodek Jagiellonski and then took part in the battles for Sambor, Drohobych and Stanislaviv, on the Dniester and Zbrucz.
In the Polish-Bolshevik War, until July 1920, he took part in the battles of Korosten, Koziatyn and Zukowiec, Berezina, Neman and Bug river. In August, he participated in the victorious battle at Baboszewo, before being transported to the region of Lviv, where, after heavy fighting took Rohatyn and in pursuit of the enemy came to Wisniowka. After the war he was deployed in Kutno and Leczyca.
In the May 1926 coup, took part in the fighting in Warsaw on the side of Marshal Jozef Pilsudski.
In the composition of "Poznan" Army and later "Pomerania" Army, this regiment took part in the September Campaign 1939. From Wągrowiec by Inowrocław, and Kutno area he reached the battlefield of Bzura, where he fought until the September 18, 1939, and then the remains of the regiment crossed the Bzura and by the Kampinos Forest reached Warsaw. After the September Campaign the regiment was disbanded.
/wiki/37_£ęczycki_Pułk_Piechoty
Other links to pages about this 37th regiment:
37pp.prv.pl/pl/001
37pp.fora.pl (Polish forum about 37th IR)
kutno.naszemiasto.pl/tag/leczycki-pulk-piechoty.html