A21 road (Northern Ireland) Wikipedia
The A21 is a road in County Down in Northern Ireland. The route commences in Bangor, passing through Newtownards, Comber, and Ballygowan, and finishes on the northern outskirts of Ballynahinch.
There are two dual carriageway sections; between Bangor and Newtownards, and between Newtownards and Comber. The second of these passes near the northern shores of Strangford Lough through some of the best agricultural land in Ireland in the vicinity of Comber. This section also passes within 2 miles of Scrabo Tower.