Down Cathedral, the Cathedral Church of the Holy and Undivided Trinity, is a Church of Ireland cathedral located in the town of Downpatrick in Northern Ireland. It stands on Cathedral Hill overlooking the town. It is one of two cathedrals in the Diocese of Down and Dromore. The cathedral is the centre point of Downpatrick, a relatively new name for the settlement, having only come into usage in the seventeenth century.

Downpatrick is a town in County Down, Northern Ireland. It is on the Lecale peninsula, about 21 mi (34 km) south of Belfast. In the Middle Ages, it was the capital of the Dál Fiatach, the main ruling dynasty of Ulaid. Its cathedral is said to be the burial place of Saint Patrick. Today, it is the county town of Down and the joint headquarters of Newry, Mourne and Down District Council. Downpatrick had a population of 11,545 according to the 2021 Census.