The first known inhabitants of the Dublin region were hunter-gatherers living during the Middle Stone Age, around 5500 BC.

The first farmers appeared shortly after 4000 BC. Evidence of their culture survives in the burial cairns, passage tombs, portal tombs and wedge tombs in the Dublin Mountains and on the coastal lowlands. Archaeological excavations have uncovered prehistoric copper axe-heads, bronze and gold artifacts, and iron age items.  The existence of ringforts or ráthsmay be deduced from the names of several of the modern city's suburbs: Rathmines, Rathgar, Rathfarnham etc

When contemporary records began in the 5th century, there was a thriving community of farmers and fishermen in existence in the vicinity of Cornmarket and High Street.

The two early settlements were called “Ath Cliath” and Duiblinn. The Viking settlement of about 841 was known as Dyflin, from the Irish Duiblinn ("black pool"), which also led to the modern English name.