Mapping city, town and country since 1824: the Ordnance Survey in Ireland - RIA Library/IHTA Lunchtime Lectures Lecture on the genesis and thrust of the great 6" Survey of Ireland by the Ordnance Survey: the maps, memoirs, letters and technical innovations which resulted. The subsequent applications of the maps for Griffith's Valuation, electoral boundary maps and other surveys; the heritage for academic research.

1. Royal Irish Academy
Lunchtime Lectures
1 October 2014
The Ordnance Survey Six-Inch
Mapping Project: Political and
Cultural Agendas

2. Benchmarks :
1791 – Foundations of the O.S. in Britain.
1820 (to 1846) – Col. Thomas Colby appointed head of the O.S.
1824 – Decision to map the whole of Ireland at very large 6’’ scale; Colby
begins triangulation in the summer of 1825.
1825 – Separate Boundary Commission formed, led by Richard Griffith.
1828 (to 1846) – Lieut. (later Capt.) Thomas A Larcom in charge of O.S.
Headquarters in Ireland (Mountjoy House, Phoenix Park).
1830 – He establishes Topographical Department under George Petrie with
John O’Donovan, Eugene O’Curry, et.al.,
1830-31 – Revision of earliest surveyed counties required.
1833-46 – Publication of first edition six-inch maps for each county, from
Londonderry (1833) to Kerry (1846).
1837 – First (and only) County Memoir published.
1846 – Griffith’s Tenement Valuation begun.
1846(May) – Larcom removed from the O.S.
1846(Nov.) – Major-General Colby steps down as head of O.S.
{See Andrews(NB), Hewitt, Doherty, et.al.,}

3. Thomas Spring Rice: Liberal MP from
Limerick, in favour of reforms – including
Catholic Emancipation – in Ireland. Chair of
1824 Select Committee on Survey of
Ireland. Later Chancellor of the Exchequer
and involved in demise of Memoir.

4. Thomas Colby

5. Richard Griffith 1784-1878

6. The Principal Triangulation of
Ireland.

7. Districts and district offices of the 6-inch
detail survey
All numbered figures from J H Andrews (A Paper Landscape)

8. State of the 6-inch detail survey, 1830

9. 1829 1832 1857
Need for revisions
Monaghan, part of 6’’ sheet 19,
1835-36
Part of 6’’ sheet 26 Co. Londonderry

10. Survey dates of completed
1st edition 6-inch sheets

12. Thomas Larcom

16. From G M Doherty

17. Eugene O’Curry
from G M Doherty

18. Fieldwork for the Memoir
Series 1830-1840
From G M Doherty

20. Clogheen – Burncourt before and after Famine

21. Civil Parishes as surveyed and
mapped by the Ordnance
Survey

22. Of Children under 5 yrs
1841 - 1851