The Armagh rail disaster happened on 12 June 1889 near Armagh, County Armagh, in Ireland, when a crowded Sunday school excursion train had to negotiate a steep incline; the steam locomotive was unable to complete the climb and the train stalled. The train crew decided to divide the train and take forward the front portion, leaving the rear portion on the running line. The rear portion was inadequately braked and ran back down the gradient, colliding with a following train.

Armagh is the county town of County Armagh and a city in Northern Ireland, as well as a civil parish. It is the ecclesiastical capital of Ireland – the seat of the Archbishops of Armagh, the Primates of All Ireland for both the Roman Catholic Church and the Church of Ireland. In ancient times, nearby Navan Fort was a pagan ceremonial site and one of the great royal capitals of Gaelic Ireland. Today, Armagh is home to two cathedrals and the Armagh Observatory, and is known for its Georgian architecture.