The name of the town is believed to have derived from the Irish Prince, Lathar who owned the lands around Larne in ancient times. The area became known as Lathar-na, and was finally shortened to Larne. Both fossils and prehistoric human artefacts have been found in the sea cliffs. Larne was one of the earliest Viking settlements in Ireland, who also called it "Ulfreksfjord" (the name of the present-day townland, "Olderfleet", is derived from this Viking name), and Viking burial sites have been discovered in the area. Norse pirates used Larne Lough as a base in the tenth and eleventh centuries; Edward Bruce, brother of Robert, landed here in 1315 with a force of six thousand men to urge the Irish to overthrow the English; and in 1914, the Ulster Volunteers, opposed to the Irish Home Rule Bill, landed German arms here.
Today, Larne is a busy market town.