The Ordnance Survey began the first modern, scientific mapping of Ireland in 1824. The map scale was six inches to an English statute mile.

Citation: Townland Survey of the County of Armagh, Ordnance Survey of Ireland. Marsh's Library Exhibits ‘Mapping History’ curated by Annaleigh Margey, Jason McElligott and Sue Hemmens with Armagh Robinson Library; Held by Armagh Robinson Library; accessed December 7, 2023, https://www.marshlibrary.ie/digi2/exhibits/show/maps/item/583