Youngest Countries in the World: South Sudan, Kosovo and the Surprises Below Them

The youngest country in the world is South Sudan, which became independent from Sudan on 9 July 2011 and joined the United Nations as its 193rd member five days later. Next come Kosovo, which declared independence from Serbia on 17 February 2008 but is recognised by only about 110 UN member states, and then Montenegro and Serbia, which both became separate sovereign states in June 2006 when their union broke up. Timor-Leste (20 May 2002), Palau (1 October 1994) and Eritrea (24 May 1993) complete the next tier. Those dates come from Wikipedia’s List of modern sovereign states by date of formation, which covers the 193 UN members, the two observer states and Kosovo. The top of the list is predictable; the more interesting part is which countries turn up unexpectedly, and which famous ones narrowly miss.

South Sudan, Kosovo and Montenegro: the three that everyone expects

South Sudan is the clear first. Its independence was the result of the 2005 Naivasha Agreement that ended decades of civil war between the government in Khartoum and the Sudan People’s Liberation Army/Movement. A referendum held from 9 to 15 January 2011 produced a 98.83% vote for separation, and on 9 July 2011 South Sudan became Africa’s 54th independent country, with its capital at Juba. It joined the African Union on 27 July 2011. At 15 years old in 2026, it is the only UN member admitted since 2006. Its first years were hard: in December 2013 President Salva Kiir accused his former deputy Riek Machar of attempting a coup, and the civil war that followed lasted until 2018, displacing millions. The country has since been governed by a coalition of the former warring factions, with UN peacekeepers of the UNMISS mission still deployed.

Kosovo is second by date but carries an asterisk. After the 1998–99 war, UN Security Council Resolution 1244 of 10 June 1999 placed it under UN administration (UNMIK) with a NATO-led force, KFOR, and affirmed the territorial integrity of Yugoslavia, whose legal successor is Serbia. Kosovo declared independence on 17 February 2008. As of December 2025, at least 110 of the 193 UN member states recognised it, including all seven G7 countries. Serbia does not, and neither do China, Russia, India or Brazil. Kosovo itself claims 120 recognitions and Serbia counts 84, arguing that some countries have withdrawn theirs. Within the European Union, 22 of the 27 members recognise Kosovo. Despite the dispute, the two governments have had normalised economic relations since 2020 and have agreed not to obstruct each other’s path towards EU membership, and under an EU-brokered arrangement Kosovo takes part in some international forums as “Kosovo*”, with a footnote referring to Resolution 1244. This article lists Kosovo by its declaration date without taking a position on its status.

Montenegro’s path was the narrowest in the table. Its referendum on 21 May 2006 needed 55% to pass and got 55.5%. Parliament made a formal declaration of independence on 3 June 2006, ending the State Union of Serbia and Montenegro. All five permanent members of the UN Security Council had recognised the preliminary result by 23 May, and Montenegro joined the UN that year. Eleven years later, on 5 June 2017, it became a member of NATO.

Serbia in 2006: the surprise on the list

Serbia is the entry that surprises most readers, because the Serbian nation, its church and its first modern principality are far older than most of Europe’s states. But the list measures the current state, not the nation. After Yugoslavia broke up, the Federal Republic of Yugoslavia became the looser State Union of Serbia and Montenegro in February 2003. When Montenegro left, Serbia’s parliament declared on 5 June 2006 that Serbia was the union’s legal successor, which dissolved the union and closed the last chapter of Yugoslavia’s break-up. Serbia kept the union’s UN seat, but the sovereign Republic of Serbia in its present form dates only from June 2006, which makes it younger than Palau, Eritrea or Timor-Leste.

The same logic explains why Montenegro and Serbia share a place: neither seceded from the other in the usual sense. The union simply stopped existing, leaving two states where there had been one.

Timor-Leste, Palau, Eritrea and the 1993 cluster

Timor-Leste was a Portuguese colony until 1975, when it was invaded and annexed by Indonesia. In a UN-organised vote on 30 August 1999, voters rejected an offer of special autonomy within Indonesia; mass violence followed, an international force (INTERFET) was sent in, and the territory passed through UN administration before becoming independent on 20 May 2002, the first new sovereign state of the 21st century. Its capital is Dili, and its 2022 census counted just over 1.34 million people. It applied to join ASEAN in 2011, was accepted in principle in November 2022, and was admitted as the bloc’s 11th member on 26 October 2025 at the summit in Kuala Lumpur.

Palau is the list’s quiet entry. It adopted a constitution and became the Republic of Palau on 1 January 1981, and signed a Compact of Free Association with the United States in 1982, but its independence took effect only when that compact entered into force on 1 October 1994. It was the last part of the UN Trust Territory of the Pacific Islands to become independent. With about 340 islands and 466 km², it is also one of the world’s smallest countries.

Eritrea had a longer road. Federated with Ethiopia under a UN decision in the early 1950s, it was formally annexed by Ethiopia in 1962. After three decades of war it voted in April 1993, by 99.83% on a turnout above 98%, for independence, which it celebrates on 24 May 1993. The Czech Republic and Slovakia are the peaceful counterpart: the “Velvet Divorce” took effect at the end of 31 December 1992, with no referendum, and both states came into being on 1 January 1993.

Near-misses from 1990 to 1992: Namibia, Yemen, the Soviet successors and Germany

Just outside the ten sits a crowded period. Bosnia and Herzegovina, in tenth place, proclaimed independence from Yugoslavia on 3 March 1992. Before it come Slovenia (25 June 1991), North Macedonia (8 September 1991) and Croatia (8 October 1991), and the Soviet Union’s break-up puts 13 states on the list with 1991 dates, from Georgia (9 April) and Estonia (20 August) to Kazakhstan (16 December) and Russia, whose date is given as 26 December 1991. Two Baltic states count from 1990: Lithuania from 11 March and Latvia from 4 May.

Two countries of 1990 are easy to forget. Namibia became independent from South Africa on 21 March 1990 after the South African Border War, and Yemen as it exists today was created on 22 May 1990 when North and South Yemen united. Further back, the Marshall Islands (21 October 1986) and the Federated States of Micronesia (3 November 1986) became sovereign under their own compacts with the United States.

The most famous near-miss is Germany. The list gives Germany a “date of last subordination” of 15 March 1991, when the Two Plus Four Treaty, under which France, the Soviet Union, the United Kingdom and the United States gave up their remaining rights over Germany, came into force after reunification in October 1990. Germany is not a new state, though: East Germany joined the existing Federal Republic, and Germany dates its founding far earlier. Our guide to the world’s newest flags covers how several of these states chose new national symbols.

Bougainville in 2030? The next likely entry

The strongest candidate to take South Sudan’s place is Bougainville, an autonomous region of Papua New Guinea. A non-binding referendum held between 23 November and 7 December 2019 produced a 98.31% vote for independence, following a 2001 agreement that ended a civil war fought from 1988 to 1998. In July 2021 the two governments agreed on independence by 2027, subject to ratification by Papua New Guinea’s parliament, and in July 2026 a Bougainville leaders’ forum recommended 1 September 2030 as the target date. Ratification by Papua New Guinea’s parliament was still pending in August 2026, when the Joint Supervisory Body of the two governments signed off its final consultation documents.

Youngest by population: Niger at a median age of 15.2

“Youngest country” has a second meaning: the one with the youngest people. By median age, the age that splits a population into two equal halves, the answer is different. The CIA World Factbook’s 2024 estimates put Niger lowest at 15.2 years, followed by Uganda (16.2), Angola (16.3), Mali (16.4) and Chad (16.7). South Sudan, the youngest state, has a median age of 18.7. At the other end, Monaco (56.9) and Japan (49.9) are the oldest sovereign states. For the full list see our ranking of countries with the youngest populations, and for the newest state in detail, our South Sudan country guide.