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Leather bound volumes shelved in a map case with county names embossed on the spines.
Ordnance Survey 1st edition maps: county volumes in the Library of the Royal Irish Academy.

OS200: Spotlight on the 1st edition Ordnance Survey maps

This blog is the first in a series that marks 200 years since the first Ordnance Survey of Ireland.

Emma Rothwell

OS200 research project

This year marks 200 years since the first Ordnance Survey of Ireland. As home to a significant Ordnance Survey Archive, the Library of the Royal Irish Academy is pleased to be a partner in the OS200 research project.

OS200 is a 3-year project jointly funded by the Irish Research Council (IRC) and the Arts and Humanities Research Council (AHRC), which aims to gather historic Ordnance Survey (OS) maps and texts, currently held in disparate archives, to form a single freely accessible online resource for academic and public use. This digital platform will reconnect the First Edition Six-Inch Maps with the OS Memoirs, Letters and Name Books. In this blog series, we will highlight some of the OS archival materials held in the RIA Library.

Leather bound volumes shelved in a map case. County names are embossed on the spines.
Ordnance Survey 1st edition maps: county volumes in the Library of the Royal Irish Academy.

Ordnance Survey and the Royal Irish Academy

The British Ordnance Survey established a department in Dublin in 1824 under the leadership of Colonel Thomas Colby (1784-1852) and Captain Thomas Larcom (1801-1879). As well as working on cartographical outputs, civilian topographical workers were employed to study placenames in historical documents and to visit the regions to learn about local pronunciation. This department was also encouraged to write letters to Larcom, detailing local toponymy, archaeology and folklore uncovered in conversation with knowledgeable locals. John O’Donovan, MRIA (1806-1861), a leading authority on Irish language, was one of the most prolific members of this team. Once the 1st edition maps were published, non-cartographical materials, such as the letters, transcriptions of historical sources, sketches of buildings and antiquarian items by artists such as George Petrie, MRIA (1790-1866), George Victor du Noyer (1817-69), and William Frederick Wakeman (1822-1900), were no longer deemed to be of use to the Ordnance Survey. Due to its significance for historical studies, the Royal Irish Academy requested that this material be deposited in their Library in 1857 and this request was granted by the British government in 1861. Along with other Irish repositories, the RIA Library was also gifted a set of the 1st edition maps upon publication. Footnote 1

Black and white head and shoulders portrait of a man in military uniform.
Portrait of Sir Thomas Aiskew Larcom, MRIA (1801–79), by Sir Leslie Ward.
Oil portrait of a man in Victorian civilian clothing.
Portrait of John O’Donovan, MRIA (1806-1861), by Charles Grey. © The National Gallery of Ireland.

The first edition OS maps

The first edition OS maps, completed by 1846, were drawn on a scale of six inches to one mile. These maps are bound in volumes, arranged by county, and are available for consultation in the Reading Room. Digitised copies of the first edition maps are freely available through the website of Tailte Éireann, the state agency established in March 2023 to incorporate the former Ordnance Survey Ireland and the Property Registration Authority and Valuation Office. This digital resource displays the 1st edition OS maps as a composite map of the island of Ireland. The line breaks between original map sheets are just visible. In the printed county volumes, in most cases, an index map is included as a guide to the numbered map sheets that follow.

Map of county Carlow spread over two pages of a large bound volume.
Carlow County index map, Ordnance Survey, 1st edition.
Detail from an index map of county Carlow showing St Mullins within the boundary of map sheet 18.
Carlow County index map detail, highlighting sheet 18, Ordnance Survey, 1st edition.

Each sheet is spread across two facing pages and measures 35in (w) x 24in (h), or 89cm x 61cm, resulting in volumes of considerable weight and size. For this reason, the map sheets for large counties such as Cork and Donegal are divided between two volumes. The RIA Library copies of the maps are a very popular, frequently consulted resource. In recent years, conservation work on several volumes has been supported by generous donations.

The print volumes also include the details of the surveyors and engravers in minute type at the bottom of each sheet. Recently, we welcomed visitors to the reading room who were conducting research about a relative who worked as an OS engraver at the Phoenix Park office. With the aid of magnifying glasses, they found his name appeared on map sheets in several county volumes. Recording and sharing additional information such as this is one of the aims of the OS200 digital platform.

Detail from Carlow map showing details about surveyors and engravers responsible for the map sheet.
Carlow County map sheet detail listing the names of surveyors and engravers, Ordnance Survey, 1st edition.

Keep an eye out for our next blog to learn more about the OS archival material held here in the RIA Library and to find out about the launch of the OS200 digital resource.