1st January 1825
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The Ordnance Survey of Ireland (1829 - 1842) was the first large-scale survey of an entire country in the world. Acclaimed for their accuracy, these maps are regarded as among the finest ever produced. For the family historian, they can identify the lay of the land in the decades preceding the famine and, most importantly, the homes that had been vacated by the time of Griffith's Primary Valuation.

The Ordnance Survey Office, established in 1824, was created to carry out a military survey of the entire island of Ireland to update land valuations for land taxation purposes. The original survey at a scale of 6 inches to 1 mile was completed under the direction of Major General Colby. Ireland thus became the first country in the world to be entirely mapped at such a detailed scale. When the survey of the whole country was completed in 1846, it was a world first.

Major Thomas Frederick Colby (Director of the First OS)

A picture of Major Thomas Frederick Colby who was responsible of the Ordnance Survey of Ireland.

Particularly relevant for genealogy or those with an interest in the history of a place, these "6-inch" maps include every tiny house or cabin that was likely occupied before the Famine. The good news is that the OSI has captured this and later mapped data in a digitised format, and they are free to inspect online. 

The first edition of these maps (the 6-ich colour maps) and additional mapping data can be explored free online via OSi (Ordnance Survey Ireland) and OSNI (Ordnance Survey of Northern Ireland).

READ MORE A short history of the Ordnance Survey on Ireland    ALSO  Finding & Navigating Old Irish Maps


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Comments

  • How does this survey relate to the Griffiths Survey of Ireland, 1864. Did Griffiths use the Ordinance maps.

    EA69

    Saturday 2nd November 2019, 07:12PM
  • Yes, they did. 

    For more about the various survey maps, see Finding & Navigating Old Irish Maps.

    IrelandXO_DM

    Friday 18th December 2020, 11:30AM
  • IrelandXO_DM

    Sunday 15th May 2022, 04:13AM
  • The maps don't seem to cover NI even though it was a whole of Ireland mapping/survey exercise.

    Jambakim

    Sunday 15th May 2022, 10:27AM

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