The original village formed where six roads and a river crossed, and is the site of the ancient Queen's Fort Rath. The road south from Belfast (the A24) climbs out of a gap in the Castlereagh Hills, and splits at Carryduff, one fork (the A7) continuing to Downpatrick (via Saintfield and Crossgar), the other fork (A24) continuing via Ballynahinch to Newcastle towards Killkeel. In addition, the road westwards from the Ards Peninsula, Newtownards and Comber (the B178) crosses here en route to Hillsborough in the west. All six roads cross the small Carryduff River here (which flows northwards to eventually join the River Lagan at Minnowburn.