Serbia, officially the Republic of Serbia, is a landlocked country at the crossroads of Southeast and Central Europe, located in the Balkans and the Pannonian Plain. It borders Hungary to the north, Romania to the northeast, Bulgaria to the southeast, North Macedonia to the south, Croatia and Bosnia and Herzegovina to the west, and Montenegro to the southwest. Serbia claims a border with Albania through the disputed territory of Kosovo. Serbia has about 6.6 million inhabitants, excluding Kosovo. Its capital Belgrade is also the largest city.

Hungary is a landlocked country in Central Europe. Spanning 93,030 square kilometres (35,920 sq mi) of the Carpathian Basin, it is bordered by Slovakia to the north, Ukraine to the northeast, Romania to the east and southeast, Serbia to the south, Croatia and Slovenia to the southwest, and Austria to the west. Hungary has a population of 9.6 million, mostly ethnic Hungarians and a significant Romani minority. Hungarian, a language belonging to the Ugric branch of the Uralic language family is the official language, and Budapest is the country's capital and largest city.