Royal Irish Academy Lunchtime Lectures1 October 2014

The Ordnance Survey Six-Inch Mapping Project: Political and Cultural Agendas

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.,}

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.

Thomas Colby

Richard Griffith 1784-1878

The Principal Triangulation of Ireland.

Districts and district offices of the 6-inch detail survey

All numbered figures from J H Andrews (A Paper Landscape)

State of the 6-inch detail survey, 1830

1829 1832 1857

Need for revisions

Monaghan, part of 6’’ sheet 19, 1835-36

Part of 6’’ sheet 26 Co. Londonderry

Survey dates of completed 1st edition 6-inch sheets

Thomas Larcom

From G M Doherty

Eugene O’Curry

from G M Doherty

Fieldwork for the Memoir Series 1830-1840

From G M Doherty

Clogheen – Burncourt before and after Famine

Civil Parishes as surveyed and mapped by the Ordnance

Survey

Of Children under 5 yrs 1841 - 1851