During the Iron Age humans started using iron for making tools and weapons. The Iron Age culture in peninsular India is marked by Megalithic burial sites, which are found in several hundreds of places. On the bases of both some excavations and the typology of the burial monuments, it has been suggested that there was a gradual spread of the Iron Age sites from the north to the south. Comparative excavations carried out in Adichanallur in Thirunelveli district and in Northern India have provided evidence of a southward migration of the Megalithic culture.

The earliest clear evidence of the presence of the megalithic urn burials are those dating from around 1000 BCE, which have been discovered at various places in Tamil Nadu, notably at Adichanallur, 24 km from Tirunelveli, where archaeologists from the Archaeological Survey of India unearthed 157 urns, including 15 containing human skulls, skeletons and bones, plus husks, grains of rice, charred rice and Neolithic celts. One urn has writing inside, which, according to archaeologists from the Archaeological Survey of India, resembles early Tamil-Brahmi script, confirming it of the Neolithic period 2800 years ago. Adhichanallur has been announced as an archaeological site for further excavation and studies.

Mentions of the political situation of Tamil Nadu before the common era are found in Asoka's edicts dated c 300 BCE and, vaguely, in the Hathigumpha inscription dated c.150 BCE. The earliest epigraphical evidence in the Tamil country are that of the Pandya king Kadungon (c. 560–590 CE) who displaced the Kalabhras from the Pandyas country. —Nilakanta Sastri, "A history of South India", pp 105, 137

Ancient Tamil Nadu contained three monarchical states, headed by kings called "Ventar" and several tribal chieftaincies, headed by the chiefs called by the general denomination "Vel" or "Velir". Still lower at the local level there were clan chiefs called "kizar" or "mannar". During the third century BCE, the Deccan was part of the Mauryan kingdom, and from the middle of the first century BCE to second century CE the same area was ruled by the Satavahana dynasty. The Tamil area had an independent existence outside the control of these northern empires. The Tamil kings and chiefs were always in conflict with each other mostly over property. The royal courts were mostly places of social gathering rather than places of dispensation of authority; they were centres for distribution of resources. Gradually the rulers came under the spell of north Indian influence and Vedic ideology, which encouraged performance of sacrifices to enhance the status of the ruler.

Delhi Sultanate
Iron Age
Pallavas
Pre-historic period