The Ukrainian Insurgent Army (Ukrainian: Українська Повстанська Армія, Ukrayins’ka Povstans’ka Armiya, UPA) was an independent Ukrainian guerrilla army formed on October 14, 1942, in Volhynia. The UPA was the military branch of the Organization of Ukrainian Nationalists. The main goal of the UPA was an independent Ukraine. Its leaders were Roman Shukhevych and Stepan Bandera.
The UPA fought a broad spectrum of military forces in the area: the German Wehrmacht, the Nazi German SS, the Polish Armia Krajowa and the Soviet Red Army. The UPA also fought the Ukrainian supporters of the latter three. After World War II, UPA partisan units continued fighting the Soviet Union and communist Poland until the early 1950s, especially in Carpathian Mountains regions. It was unique among practically all resistance movements in Nazi-occupied Europe in that it had no significant foreign support, making its growth and strength an indication of its popularity among the Ukrainian people.