Down Cathedral in Downpatrick is said to hold the grave of Saint Patrick, with Saints Brigid and Columcille traditionally buried beside him - three patrons of Ireland sharing one hilltop. Nearby Saul, whose name comes from the Irish Sabhall meaning barn, is where Patrick is reputed to have said his first eucharist in Ireland, on land granted to him by a local chief. The granite slab marking the grave at Downpatrick is modern, but the cathedral itself sits on a site that has been Christian since at least the seventh century and probably much longer. Pilgrims still arrive each March. The mound called Rathkeltair, beside the cathedral hill, is older still - an Iron Age earthwork whose name preserves the memory of a hero from the Ulster Cycle of Irish mythology.

The Mournes are not large mountains by world standards - Slieve Donard reaches only 850 metres - but they look bigger than they are because they rise so suddenly from the coast. C. S. Lewis grew up looking at them from Belfast and later said they inspired the landscape of Narnia. The Mourne Wall, eighteen years of stonework completed in 1922, traces fifteen summits across the range. Tollymore Forest Park, beside Castlewellan, has played Winterfell and the Riverlands and other locations in Game of Thrones, drawing fans from across the world to the same paths Lewis once walked. The wall, the forest, the granite, the sweep down to the sea - it has been imagined so many times that even the real landscape now feels like a piece of literature.

Between the Ards Peninsula and the mainland, Strangford Lough opens like an inland sea. Vikings named the place Strangfjorthr - violent fjord - for the brutal tidal race at its narrow mouth, where 350 million tonnes of water surge through twice a day. At least seventy named islands dot the inner lough; pladdies, the local word for small islets, push the count higher. Castle Ward stands on the western shore, an eighteenth-century mansion whose owners disagreed so sharply about architecture that the front of the house is Palladian and the back is Gothic. Exploris, the Northern Ireland Aquarium at Portaferry, lets visitors meet the lough's marine life face to face - rays, sharks, the whole community that depends on those violent tides.

Down has produced more than its share of notable people for a county of half a million. Patrick Brontë, father of Charlotte, Emily, and Anne, was born here near Rathfriland - his family name was originally Brunty. Hans Sloane, born at Killyleagh in 1660, eventually amassed the collection that became the British Museum. Harry Ferguson of Dromore invented the modern tractor. James Martin of Crossgar designed the ejector seat that has saved thousands of military pilots. Eddie Irvine raced Formula 1 from Newtownards. Rory McIlroy, born in Holywood on the north coast, has played a great deal of golf at Royal County Down in Newcastle, which Golf Digest ranked number one in the world in 2024. Van Morrison wrote songs that name the loughs and headlands.

Down contains the easternmost point of Ireland at Burr Point on the Ards, and the southernmost point of Northern Ireland at Cranfield Point on Carlingford Lough. The county borders the Irish Sea to the east, Antrim to the north along the River Lagan, Armagh to the west, and Louth across the lough to the southwest. The 2021 census recorded 552,261 residents - the only county in Northern Ireland with a Protestant background majority, though Ards and North Down also reported the region's highest share of no-religion responses, 30.6 percent. Bangor became the county's newest city in December 2022. Newry, in its south, was made a city in 2002. Belfast and Lisburn straddle the northern border. The granite Mournes still sweep down to the sea, exactly the way Percy French heard them doing on that station platform.