Polish 1st Legions Infantry Division (1. Dywizja Piechoty Legionów) was a tactical unit of the Polish Army between the World Wars. Formed on February 20, 1919, partially of veterans of the I Brigade of the Polish Legions, the unit saw extensive action during the Polish-Bolshevik War and World War II. Regarded by the soldiers of the Wehrmacht as the Iron Division, it distinguished itself in the Invasion of Poland.