As per WorldPopulationReview.com, identifying oldest nations begins with defining what makes a country.
Ancient city-states like Athens, or mighty empires like Rome and Han shaped civilisations, they don't fit the modern idea of a sovereign nation.
Iran, 2600 BC
Once the cradle of mighty civilisations -- Elamites, Kassites, Mannaeans, Gutians, each shaping the region’s enduring cultural legacy -- Iran ranks among the world’s first nations.
India, 2500 BC
One of the oldest civilisations to take root, the rise of the Indus Valley Civilisation was around 2600–1900 BC, with its bustling, beautifully-planned cities like Mohenjo-daro and Harappa.
China, 1600 BC
China’s ancient journey began with the Shang Dynasty, emerging around 1600 BC in the Yellow river basin -- the earliest known Chinese state backed by both archaeology and script.
Japan, 660 BC
Legend says Emperor Jimmu, believed to be a direct descendant of sun goddess Amaterasu, ascended the throne in 660 BCE, marking the mythical birth of Japan’s imperial lineage.
Algeria, 202 BC
The country's sovereign roots started with the kingdom of Numidia, established by King Massinissa. Human presence in the region dates earlier -- there is ancient 7000 BC rock art in Tassili National Park.
San Marino, 301 AD
Established September 3, 301 AD by stonemason Marinus, the postage stamp-sized tiny nation nestled on Mount Titano proudly holds the title of the world’s oldest existing republic.
France, 843 AD
La République beginnings are often traced to the Treaty of Verdun in 843 CE, which split the Carolingian Empire and gave rise to West Francia, the earliest framework of modern France.
Austria, 976 CE
Its origins as a political entity are from when Leopold I of the Babenberg dynasty was named Margrave of Ostarrîchi, a border territory within the Holy Roman Empire.