Northern Ireland postcode data is under the Ordnance Survey of Northern Ireland.

In more recent times, the Ordnance Survey of Ireland replaced traditional ground surveying with mapping based primarily on aerial photography.

The Ordnance Survey of Ireland is established.

This includes the first Ordnance Surveys of Ireland, conducted in the early 19th century.

Ordnance Survey of Ireland (maps no. 41 and no.42)

Ligar was employed on the Ordnance Survey of Ireland until 1840.

According to the 6 inch historical maps from the Ordnance Survey of Ireland that were created in 1829, no such parish exists.

The civil parishes had some use in local taxation and were included on the nineteenth century maps of the Ordnance Survey of Ireland.

He then headed the Ordnance Survey of Ireland.

The Ordnance Survey of Ireland, from its establishment in 1824, used English miles.