The railway connection decisively promoted Eydtkuhnen's development: the Neo-Romanesque Lutheran parish church was built according to plans by Friedrich Adler and consecrated in 1889; the settlement received town privileges in 1922, when the population reached 10,000. Nevertheless, Eydtkuhnen was devastated during the Russian invasion of East Prussia in 1914 and again in 1945 during the East Prussian Offensive of the Red Army. After World War I and the Act of Independence, the border crossing led to Lithuania, while corridor trains provided the railway connection to Berlin.