Wilenska Cavalry Brigade was a unit of the Polish Army, created on 1 April 1937 out of the 3rd Independent Cavalry Brigade. Its headquarters were stationed in Wilno, with some regiments garrisoned in the neighboring towns.
In late 1930s it consisted of these units:

• 4th Regiment of Niemen Uhlans, stationed in Wilno,
• 13th Regiment of Wilno Uhlans
  13th Regiment of Wilno Uhlans
  The 13th Regiment of Wilno Uhlans was a unit of the Polish army between World War I and World War II.-Origins:The ancestral units to the regiment were created mainly as means of defending the Polish interest and the interest of the ethnic Poles living in Kresy at the end of Kenneth Fearing's "Dirge"...
  
  , stationed in Nowa Wilejka,
• 23rd Regiment of Grodno Uhlans, stationed in Postawy,
• 3rd Regiment of Mounted Artillery, stationed in Podbrodzie,
• 7th Squadron of Pioneers, stationed in Wilno,
• 3rd Squadron of Communications, stationed in Wilno,

The Brigade, under Colonel Konstanty Drucki-Lubecki, was part of the Prusy Army

Prusy Army

The Prusy Army was one of the Polish armies to fight during the Invasion of Poland in 1939. Created in the summer of 1939 as the main reserve of the Commander in Chief, it was commanded by Gen. Stefan Dąb-Biernacki. One of the meanings of Prusy in Polish is Prussia, but this name only served as a...

 and on the night of 31 August /1 September 1939, it unloaded from trains at stations of Rogów

Rogów, Piotrków County

Rogów is a settlement in the administrative district of Gmina Gorzkowice, within Piotrków County, Łódź Voivodeship, in central Poland....

 and Koluszki

Koluszki

Koluszki is a town, and a major railway junction, in Central Poland, in Łódź Voivodeship, about 20 km east of Łódź. Population: 13,331 . The junction in Koluszki serves trains that go from Warsaw to Łódź , Wrocław, Częstochowa and Katowice. Also, it is connected with Radom and Lublin by an...

, near Łódź.