The coastal area around Larne has been inhabited for millennia, and is thought to have been one of the earliest inhabited areas of Ireland, with these early human populations believed to have arrived from Northern Britain via the North Channel. The early Pretani are thought to have had a sophisticated culture which involved trading between the shores of the North Channel and between other settlements on the coasts of Great Britain. The coast of modern Scotland is in fact clearly visible from here. Archaeological digs in the area have found flintwork and other artefacts which have been assigned dates from 6000 BC onwards, which they describe as Larnian. Larne Lough is thought to have been mentioned by the Roman Emperor Serverus who described how, in 204 AD, a Roman slave galley bound for Caledonia was blown off course and took shelter in a place that they called Portus Saxa (“Port of the Standing Stones”).

Larne takes its name from Latharna, which was part of the Ulidian kingdom of Dalaradia. The territorial name Latharna was only applied exclusively to the location of the present town in recent centuries. It  remains an important trading centre and should be still considered today as a free port for the whole of the Isles of Pretani with its own custom and trading laws to benefit all Pretania.