This was the beginning of the modern Austrian party Social Democratic Party of Austria. On 26 September 1928 the Lower Austrian State Government endowed Hainfeld with town privileges. After World War II Hainfeld was the second most destroyed Austrian city behind Wiener Neustadt and part of the Soviet occupation zone in Allied-occupied Austria.
The establishment of the modern Austrian Social Democratic Party of Austria began here. In 1928, the Lower Austrian State Government conferred town status on Hainfeld on September 26. Following World War II, Hainfeld was severely affected and became part of the Soviet-controlled zone in post-war Allied-occupied Austria.