From there it meets the Irish Sea coast of the Ards Peninsula at Cloughey, and follows it through Portavogie, Ballyhalbert, Millisle and Donaghadee to Bangor, County Down, from where it becomes a major dual carriageway leading to Belfast.

Along this stretch and further out the Shore Road, the main route runs along the line of the M2 and M5, to a point where the M5 ends in Newtownabbey in the northern suburbs of Belfast.

Early in the 19th century, in the reign of William IV, the Commissioners of Public Works in Ireland reported that the Glens of Antrim were "cut off from any reasonable communication by the badness of roads over mountains and slopes varying from 1 in 6 to 1 in 12".

Before the road was built they sailed across the North Channel to Scotland to trade their goods, because the short sea crossing was easier than travel by land to the nearest market town.

In his report to the Commissioners[6] Bald stated: "30,0000 cubic yards of rock have been hurled down on the shore almost entirely by blasting, which has been executed by care and judgement.

But there were frequent rockfalls because the geology of the Antrim Coast is Ulster White Limestone, greatly faulted and fissured, which bears a considerable overburden of basalt, also weathered and rotten near the surface.

The council opened a quarry and began to build a new embankment, but on the night of 31 October 1968 there was a one in 70-year storm that washed away the part of the causeway that had not yet been protected by rock armour.

[8] William Bald was a civil engineer who left a great legacy to the people of the Glens of Antrim, and created one of the finest tourist routes in the World.

[10] Owing to its length and the fact that it follows the coast, the road passes a large number of Northern Ireland's tourist attractions.