An Ordnance Survey Bench Mark is a surveying mark made by the Ordnance Survey to record heights above Ordnance Datum. They are typically found on buildings, bridges, or other structures and are used as reference points for altitude measurements.

Ordnance Survey International was created in 1946.

Gillian M. Doherty has written:

'The Irish Ordnance Survey' -- subject(s): Antiquities, Cartography, Historiography, History, Irish National characteristics, Maps, Ordnance Survey (Ireland)

There are many places where one can find an ordnance survey map. One looking to find an ordnance survey map should visit the official Ordnance Survey website and click the 'Get a Map' link.

Patrick McWilliams has written:

'People and Places (Index to Ordnance Survey Memoirs of Ireland)'