Croatia, officially the Republic of Croatia, is a country in Central and Southeastern Europe, on the coast of 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. The Croatian archipelago contains over 1,000 islands and islets, the largest overseas territory on the Adriatic Sea. Its capital, largest city and main cultural and economic centre is Zagreb. Major urban centers include Split, Rijeka, and Osijek. The country is composed of twenty counties spanning 56,594 square kilometres (21,851 square miles) within four administrative regions. Croatia has a population of nearly 3.9 million as of 2026.
Croatian history began with the 6th century arrival of the Croats to Roman Illyria. Settled as two duchies a century later, Croatia was granted independence in 878 under Duke Branimir and elevated into a kingdom under King Tomislav in 925. The Trpimirović dynastic succession crisis placed Croatia into a personal union with Hungary in 1102. In 1527, amid Ottoman conflict, Croatia aligned with the Habsburg monarchy. It reorganized into the State of Slovenes, Croats, and Serbs before merging into the Kingdom of Yugoslavia in 1918. During World War II, most of Croatia was invaded by the Axis powers who installed a puppet state known as the Independent State of Croatia. A resistance movement restored sovereignty, emerging as the Socialist Republic of Croatia within the Socialist Federal Republic of Yugoslavia in 1943. Croatia declared independence from Yugoslavia in 1991, successfully fighting the War of Independence until 1995.
Modern Croatia is a representative democracy with a prime minister, president, and unicameral parliament. Its constitution ensures separation of powers between the executive, legislative, and judicial branches. Croatian politics reflect a multi-party system. Croatia is part of many international organizations and forums including the European Union, United Nations, WTO, and NATO, among others. It exerts regional influence as a small power in Europe, particularly within neighboring Southeast Europe. Since 1999, the Croatian Armed Forces have deployed internationally for a variety of peacekeeping missions and military interventions. Croatia was elected to serve on the non-permanent seat of the UN Security Council from 2008 to 2009.
A developed country, Croatia has an advanced economy considered high-income and dominated by its service, industrial, and agricultural sectors. Its tourism sector is prominent, generating significant economic activity across the country. Croatia has heavily invested in infrastructure, especially in transport routes and facilities along European corridors. An emerging energy power in Europe, it has strategic investments in liquefied natural gas, geothermal networks, and electric transport. It has extensive biodiversity, wildlife, and natural resources across its geography. Croatia provides social security, universal health care, and subsidized primary and secondary education while supporting culture through media and publishing.
Croatia's non-native name derives from Medieval Latin Croātia, itself a derivation of North-West Slavic *Xərwate, by liquid metathesis from Common Slavic period *Xorvat, from proposed Proto-Slavic *Xъrvátъ which possibly comes from the 3rd-century Scytho-Sarmatian form attested in the Tanais Tablets as Χοροάθος (Khoroáthos. Alternate forms are Khoróatos and Khoroúathos). The origin of the ethnonym is uncertain, but most probably is from Proto-Ossetian / Alanian *xurvæt- or *xurvāt-, in the meaning of "one who guards" ("guardian, protector").
The oldest preserved record of the Croatian ethnonym's native variation *xъrvatъ is of the variable stem, attested in the Baška tablet in style zvъnъmirъ kralъ xrъvatъskъ ("Zvonimir, Croatian king"), while the Latin variation Croatorum is archaeologically confirmed on a church inscription found in Bijaći near Trogir dated to the end of the 8th or early 9th century. The presumably oldest stone inscription with fully preserved ethnonym is the 9th-century Branimir inscription found near Benkovac, where Duke Branimir is styled Dux Cruatorvm, likely dated between 879 and 892, during his rule. The Latin term Chroatorum is attributed to a charter of Duke Trpimir I of Croatia, dated to 852 in a 1568 copy of a lost original, but it is not certain if the original was found to be older than the Branimir inscription.
The area known as modern Croatia was inhabited throughout the prehistoric period. Neanderthal fossils dating to the middle Palaeolithic period were unearthed in northern Croatia, best presented at the Krapina site. Remnants of Neolithic and Chalcolithic cultures were found in all regions. The largest proportion of sites is in the valleys of northern Croatia. The most significant are Baden, Starčevo, and Vučedol cultures. Iron Age hosted the early Illyrian Hallstatt culture and the Celtic La Tène culture.
The region of modern-day Croatia was settled by Illyrians and Liburnians, while the first Greek colonies were established on the islands of Hvar, Korčula, and Vis. In 9 AD, the territory of today's Croatia became part of the Roman Empire. Emperor Diocletian was native to the region. He had a large palace built in Split, to which he retired after abdicating in AD 305. During the 5th century, the last de jure Western Roman Emperor Julius Nepos ruled a small realm from the palace after fleeing Italy in 475.
The Roman period ends with Avar and Croat invasions in the late 6th and first half of the 7th century and the destruction of almost all Roman towns. Roman survivors retreated to more favourable sites on the coast, islands, and mountains. The city of Dubrovnik was founded by such survivors from Epidaurum.
The ethnogenesis of the Croats is a subject of scholarly discussion, reflecting the complexity of early medieval migrations and the integration of diverse populations. The predominant scholarly consensus, based on historical chronicles, proposes that the White Croats originated as a Slavic group that migrated from White Croatia during the Migration Period. Conversely, the Iranian theory proposes Sarmatian-Alanic origin of Proto-Croats, based on Tanais Tablets containing Ancient Greek inscriptions of given names Χορούαθος, Χοροάθος, and Χορόαθος (Khoroúathos, Khoroáthos, and Khoróathos) and their interpretation as anthroponyms related to the Croatian ethnonym.
According to the work De Administrando Imperio written by 10th-century Byzantine Emperor Constantine VII, Croats settled in the Roman province of Dalmatia in the first half of the 7th century after they defeated the Avars. Although there exist some scholarly disputes about the account's reliability and interpretation, recent archaeological data has established that the migration and settlement of the Slavs/Croats was in the late 6th and early 7th century. Eventually, a dukedom was formed, Duchy of Croatia, ruled by Borna, as attested by chronicles of Einhard starting in 818. The record represents the first document of Croatian realms, vassal states of Francia at the time. Its neighbor to the North was Principality of Lower Pannonia, at the time ruled by duke Ljudevit who ruled the territories between the Drava and Sava rivers, centred from his fort at Sisak. This population and territory throughout history was tightly related and connected to Croats and Croatia.
Christianisation of Croats began in the 7th century at the time of archon Porga of Croatia, initially probably encompassed only the elite and related people, but mostly finished by the 9th century. The Frankish overlordship ended during the reign of Mislav, or his successor Trpimir I. The native Croatian royal dynasty was founded by duke Trpimir I in the mid 9th century, who defeated the Byzantine and Bulgarian forces. The first native Croatian ruler recognised by the Pope was duke Branimir, who received papal recognition from Pope John VIII on 7 June 879. Tomislav was the first king of Croatia, noted as such in a letter of Pope John X in 925. Tomislav defeated Hungarian and Bulgarian invasions. The medieval Croatian kingdom reached its peak in the 11th century during the reigns of Petar Krešimir IV (1058–1074) and Dmitar Zvonimir (1075–1089). When Stjepan II died in 1091, ending the Trpimirović dynasty, Dmitar Zvonimir's brother-in-law Ladislaus I of Hungary claimed the Croatian crown. This led to a war and personal union with Hungary in 1102 under Coloman.