- Hungary has a population of around 10 million people and its official country code is HU. It joined the European Union in 2004. - The capital and largest city of Hungary is Budapest, with a population of around 1.7 million people, or 17% of Hungary's total population. Around 55% of Hungarians are Catholic. - Hungary has lost around 65% of its territory following World War I due to the Treaty of Trianon. Its longest river is the Danube, and its highest point is Kékes Mountain at 1,014 meters.