The Iron Rhine Treaty (1873) was a treaty between Belgium and the Netherlands regarding the passage of the international Iron Rhine railway line from Antwerp (Belgium) to Mönchengladbach (Germany) over Dutch territory in Limburg (the Netherlands). This put into effect a Belgian right to access to Germany through Dutch territory established in the 1839 Treaty of London. The railway line, generally known as the "Iron Rhine", was to be run as a concession by the Belgian Compagnie du Nord.