In the aftermath of the First World War, partitioned Poland regained its independence. As the young nation attempted to delineate its new borders and defend them from threatening Others, in particular the atheist Soviet Russia, the symbol of the cross came to denote an ethno-nationalist vision of the country’s future. Focusing on three highly controversial monumental crosses erected in the contested Polish–Lithuanian/Belarusian/Ukrainian borderlands, I show how Catholic symbols in the service of the emerging nation-state helped to legitimate Poland’s claim to the multi-ethnic territories of the former Grand Duchy of Lithuania and communicated military dominance and moral supremacy over Lithuanians, Belarusians, Ukrainians, and Jews, who had come to be symbolically excluded from the national fold.