The Geography of Croatia is defined by its location—it is described as a part of Central Europe and Southeast Europe, a part of the Balkans and Mitteleuropa. Croatia's territory covers 56,594 km² (21,851 sq mi), making it the 127th largest country in the world. Bordered by Bosnia and Herzegovina and Serbia in the east, Slovenia in the west, Hungary in the north and Montenegro and the Adriatic Sea in the south, it lies mostly between latitudes 42° and 47° N and longitudes 13° and 20° E. Croatia's territorial waters encompass 18,981 square kilometres (7,329 sq mi) in a 12 nautical miles (22 km; 14 mi) wide zone, and its internal waters located within the baseline cover an additional 12,498 square kilometres (4,826 sq mi).

The Pannonian Basin and the Dinaric Alps, along with the Adriatic Basin, represent major geomorphological parts of Croatia. Lowlands make up the bulk of Croatia, with elevations of less than 200 metres (660 ft) above sea level recorded in 53.42% of the country. Most of the lowlands are found in the northern regions, especially in Slavonia, itself a part of the Pannonian Basin plain. The plains are interspersed with horst and graben structures, believed to have broken the Pliocene Pannonian Sea's surface as islands. The greatest concentration of ground at relatively high elevations is found in the Lika and Gorski Kotar areas in the Dinaric Alps, but high areas are found in all regions of Croatia to some extent. The Dinaric Alps contain the highest mountain in Croatia—1,831-metre (6,007 ft) Dinara—as well as all other mountains in Croatia higher than 1,500 metres (4,900 ft). Croatia's Adriatic Sea mainland coast is 1,777.3 kilometres (1,104.4 mi) long, while its 1,246 islands and islets encompass a further 4,058 kilometres (2,522 mi) of coastline—the most indented coastline in the Mediterranean. Karst topography makes up about half of Croatia and is especially prominent in the Dinaric Alps, as well as throughout the coastal areas and the islands.

Croatia (ⁱ/kroʊˈeɪʃə/ kroh-AY-shə; Croatian: Hrvatska pronounced [xř̩ʋaːtskaː]), officially the Republic of Croatia (Croatian: Republika Hrvatska  listen (help·info)), is a unitary democratic parliamentary republic in Europe at the crossroads of Central Europe, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers 56,594 square kilometres (21,851 square miles) and has diverse, mostly continental and Mediterranean climates. Croatia's Adriatic Sea coast contains more than a thousand islands. The country's population is 4.29 million, most of whom are Croats, with the most common religious denomination being Roman Catholicism.

In the early 7th century the Croats arrived in area of present-day Croatia. They organised the state into two dukedoms by the 9th century. Tomislav became the first king by 925 AD, elevating Croatia to the status of a kingdom. The Kingdom of Croatia retained its sovereignty for nearly two centuries, reaching its peak during the rule of Kings Peter Krešimir IV and Dmitar Zvonimir. Croatia entered a personal union with Hungary in 1102. In 1527, faced with Ottoman conquest the Croatian Parliament elected Ferdinand I of the House of Habsburg to the Croatian throne. In 1918, after World War I, Croatia was included in the short-lived State of Slovenes, Croats, and Serbs that declared independence from Austria–Hungary and co-founded the Kingdom of Yugoslavia. A Croatian state briefly existed during World War II as a fascist puppet state. After the war, Croatia became a founding member and a federal constituent of the Second Yugoslavia, a socialist state. In June 1991, Croatia declared independence, which came into effect on 8 October of the same year. The Croatian War of Independence was fought successfully during the four years following the declaration.