Hungary–Romania border

Prior to World War I, the eastern and southern Carpathian Mountains formed a natural border between the Austro-Hungarian Empire and Romania.^[5]

Hungary and Romania became belligerents in World War I as Romania entered the war in 1916 on the side of the Allies. During that war the part of Transylvania south of the Maros (Mureș) and east of the Szamos (Someș) had been occupied by Romania forces at the time of the cease-fire agreement of Belgrade signed on 13 November 1918.^[6] On 1 December 1918, the Great National Assembly of Alba Iulia declared union with the Kingdom of Romania. Subsequently, the Romanian forces moved further into Hungary and occupied Budapest from August to mid-November 1919.^[7]

The Treaty of Trianon finalized the armistice between the Allies and Hungary.^[8] In the treaty Romania recovered all of Transylvania (including parts of Maramureș, Banat and Crișana),^[9][10]

Briefly during World War II, Northern Transylvania (including part of Maramureș and Crișana) was returned to Hungary under the Second Vienna Award in 1940.^[11][12] In 1944 as World War II drew to a close and Romania joined the war against Germany, the Allies agreed de facto to the Trianon boundaries, and this was confirmed at the Paris Peace Conference in 1946, and by the subsequent peace treaties formalized in 1947.^[12][13]

The Hungarian–Romanian border begins at a tripoint located in the historical region of the Banat, 15 km (9.3 mi) south-east of the Hungarian town of Szeged, where the border between Hungary and Serbia intersects the land border between Romania and Serbia. It generally runs south-south-westwards/north-north-eastwards across the Pannonian Basin to another tripoint located on the Tur river, 16 km (9.9 mi) north of the Romanian town of Satu Mare, where the Hungarian-Ukrainian border intersects the land border between Romania and Ukraine.

• Hungary–Romania relations
• Union of Hungary and Romania