During the Middle Ages, Naßfeld Pass was part of an important trade route between the Duchy of Carinthia and the Republic of Venice. It lost its significance with the extension of mountain roads via neighbouring Tarvis and Predil Pass. Several expansion projects were started from the 17th century onwards, however, the present-day highway was not built until 1915 amidst World War I, when the Austro-Hungarian Army urged for a transport route to the Italian Front. Like at nearby Plöcken Pass, Naßfeld saw heavy fighting when Italian Alpini troops tried to push northwards into Carinthia.