Croatia, officially the Republic of Croatia, is a country at the crossroads of Central and Southeast Europe. Its coast lies entirely on the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herzegovina and Montenegro to the southeast, and shares a maritime border with Italy to the west and southwest. Its capital and largest city, Zagreb, forms one of the country's primary subdivisions, with twenty counties. The country spans 56,594 square kilometres (21,851 square miles), and has a population of nearly 3.9 million.
The Croats arrived in the late 6th century. By the 9th century, they had organized the territory into two duchies. Croatia was first internationally recognized as independent on 7 June 879 during the reign of Duke Branimir. Tomislav became the first king by 925, elevating Croatia to the status of a kingdom. During the succession crisis after the Trpimirović dynasty ended, Croatia entered a personal union with Hungary in 1102. In 1527, faced with Ottoman conquest, the Croatian Parliament elected Ferdinand I of Austria to the Croatian throne. In October 1918, the State of Slovenes, Croats and Serbs, independent from Austria-Hungary, was proclaimed in Zagreb, and in December 1918 merged into the Kingdom of Yugoslavia. Following the Axis invasion of Yugoslavia in April 1941, most of Croatia was incorporated into a Nazi-installed puppet state, the Independent State of Croatia. A resistance movement led to the creation of the Socialist Republic of Croatia, which after the war became a founding member and constituent of the Socialist Federal Republic of Yugoslavia. On 25 June 1991, Croatia declared independence, and the War of Independence was successfully fought over the next four years.
Croatia is a republic and a parliamentary liberal democracy. It is a member of the European Union, the Eurozone, the Schengen Area, NATO, the United Nations, the Council of Europe, the OSCE, the World Trade Organization, and a founding member of the Union for the Mediterranean. An active participant in United Nations peacekeeping, Croatia contributed troops to the International Security Assistance Force and filled a nonpermanent seat on the United Nations Security Council for the 2008–2009 term. Since 2000, the Croatian government has invested in infrastructure, especially transport routes and facilities along the Pan-European corridors.
Croatia is classified by the World Bank as a high-income economy and ranks highly on the Human Development Index. Service, industrial sectors, and agriculture dominate the economy. Tourism is a significant source of revenue for the country, which is ranked among the 20 most popular tourist destinations. The state controls a part of the economy, with substantial government expenditure. The European Union is Croatia's most important trading partner. Croatia provides social security, universal health care, and tuition-free primary and secondary education while supporting culture through public institutions and corporate investments in media and publishing.