Virtual Record Treasury of Ireland

Research Guide

Chief Secretary’s Office

Research Guide Subtitle: A guide to substitute and replacement records
Contributors: Timothy Murtagh
First published: 2022

Why use this guide?

Use this guide for advice on how to find and use replacement materials for Chief Secretary’s Office documents destroyed in 1922. 

What was the Irish Chief Secretary’s Office ?

From the sixteenth century, the Chief Governor of Ireland (also known as the Lord Lieutenant or Lord Deputy) always had a primary or ‘chief’ secretary. This Chief Secretary acted as their main assistant in organizing and pursuing policy. The Chief Secretary was the Lord Lieutenant’s nominee, coming to Ireland at the beginning of the Lord Lieutenant’s time in office, and usually leaving when his time was over.. During this tenure, however, the Chief Secretary served at the Lord Lieutenant’s pleasure as the head of his secretariat. In addition, the Chief Secretary usually held a seat in the Irish House of Commons, acting as the spokesman for government policy in the parliament. The Chief Secretary was assisted by two under-secretaries, who in turn oversaw the ‘civil’ and ‘military’ departments within the office. Below is a diagram showing the basic structure of the CSO for the period up to 1818. 

By the late eighteenth century,  the Office of the Chief Secretary had become the main supervising agency within the bureaucracy of the central government. The Chief Secretary’s Office (hereafter CSO) was in charge of supervising the machinery of the Irish administration, overseeing the various government departments. Crucially, the CSO coordinated between government departments in England with their counterparts or branch offices in Ireland.

 The duties of the CSO included :

  • Issuing all orders relating to the military and the treasury
  • Overseeing the payment of the military and civil establishments.
  • Handling all correspondence with the commissioners of the Irish Revenue and the Board of Works.
  • It also had a broad responsibility for the administration of justice in Ireland.

For these reasons, CSO has been described as ‘the nerve centre of the Irish administration’.  Moreover, during the nineteenth century, the CSO would also absorb the Irish Privy Seal Office (in 1829) and then the Privy Council Office (in 1852). By the latter decades of the nineteenth century, the Chief Secretary was also technically at the head of three other departments, being the chairman of the Local Government Board (LGB), the president of the Department of Agriculture and Technical Institutions (DATI), and chairman of the Congested Districts Board (CDB). In addition to these roles, after 1919 the Chief Secretary also became Minister of Health for Ireland, although assisted by an Irish Public Health Council. While the aforementioned roles were technically separate from the CSO, that these functions were fulfilled by the Chief Secretary again reflects the importance of his position and the organization beneath him. The CSO continued to be the central administrative office of British government in Ireland up until 1922, after which its role was to oversee the transfer of administrative function to the new institutions of the recently established Irish Free State.

What sources are available?

What was destroyed in 1922:

Within Herbert Wood’s 1919 Guide to the public records, a full eighteen pages are devoted to the contents of the Chief Secretary’s Office, divided into ‘Civil’ and ‘Military’ departments of the CSO.  These records are divided into 202 different series (136 civil series and 66 military series). However, many of these series are further divided into numerous sub-series. For instance, the series ‘Departmental Letters and Official Papers 1760-1831’ contains 272 different sub-series.  While there are a few series that date from the seventeenth century, the majority date from after 1700.  Most of the later series conclude in the 1830s, and there is no material listed that is later than 1848.  This is due to the fact that, for series after 1840,  the Chief Secretary’s Office retained most of the material in Dublin Castle, rather than transfer records to the Public Record Office in the Four Courts. 

Existing original materials:

A large collection of Chief Secretary’s Office  papers, dating from after 1818, have survived and are preserved in the National Archives of Ireland (NAI). These are the ‘Chief Secretary Office Registered Papers’ (CSORP), which consist of two main archival series covering the years 1818 to 1924, together with a number of sub-series within this date span. In addition to CSORP, the National Archives of Ireland also hold a collection known as the  ‘Rebellion Papers’. This collection consists of documents dating from 1790 to 1808, being mainly letters to the government concerning the activities of the United Irishmen and the Rebellion of 1798.   There are also two other smaller collections of letters to Dublin Castle from this same period, listed separately as the ‘State of the Country Papers’, first and second series.  In addition to these survivals, the National Archives of Ireland also hold a number of calendars of CSO materials.

These are calendars produced during the nineteenth century which were stored in the reading room of the Public Record Office and thus survived the fire of 1922. These calendars provide insight into the structure of the materials destroyed, usually providing names and dates of correspondence, and occasionally a description of the topic discussed. 

Existing replacements and substitutes:  

One of the most significant sources for replacement CSO materials are the large collections of State Papers held by the National Archives (UK).  During the eighteenth century, the  Lord Lieutenant regularly sent public dispatches (such as formal acknowledgements or requests) to the Secretary of State for the Southern Department, which was responsible for Irish affairs. In addition, the Lord Lieutenant often sent private dispatches, commenting on political issues and policies.  For the period 1715-1782, this material can be found in the State Papers Ireland, SP 63/372 to 480. In addition, there are entry books of letters sent by the Secretary of State to the Lord Lieutenant and his Secretary, which are located in SP 67. For a full discussion of the State Papers Ireland, see the research guide provided by the National Archives (UK):

After 1782, Irish affairs were the responsibility of the British Home Office. The bulk of correspondence between the Chief Secretary’s Office and the Home Office is located in a series in the National Archives (UK), known as the Home Office 100 series. This is a 264 volume series, dating from 1782 to 1851. The HO 100 series contains a multitude of very strong replacement and substitute materials for destroyed CSO series, both civil and military. The series contains additional papers on special subjects, such as Catholic Emancipation, Poor Law Reform, Policing and ‘outrages’, and various special commissions. 

Another significant source for replacement CSO records are the family collections of those men who held the post of Lord Lieutenant, Chief Secretary or Under-Secretary. A full list of those who held these posts can be found in J.C. Sainty ‘The Secretariat of the Chief Governors of Ireland, 1690-1800’ (see the suggested further reading below). In some cases, correspondence from relevant officials has been edited and published, often as part of the output of the Historical Manuscripts Commission in the nineteenth century. However, a very large number of relevant manuscript sources remain unpublished. 

How do I find what I am looking for?

Due to the large volume, and extensive variety, of the Chief Secretary’s Office’s business, it can be difficult to find specific replacement materials. For instance, the large State Paper collections can be challenging to use; although pre-1782 material is well served by existing calendars. The starting point for exploring these key collections is TNA Discovery, the online catalogue and guide to the National Archives (UK):

 In the case of surviving CSO series such as the Rebellion Papers, State of the Country Papers, and CSO Registered Papers, researchers are advised to consult the comprehensive guides provided by the National Archives of Ireland website:

As stated, a good approach is to identify the personal papers of figures who held significant office during the specific period the researcher is interested in. (For a listing of CSO personnel, see works by Sainty and Hughes in ‘‘Further Reading’ below). It is also useful to target the correspondence of specific departments within the CSO, i.e. ‘civil’ or ‘military’.  The inquisitive researcher will be repaid for time invested exploring catalogues of major repositories such as the British Library (, and PRONI (   

In addition, the database for Irish research provided by the National Library of Ireland (NLI)  is extremely useful for locating CSO replacement sources, both in NLI itself and in other repositories ( Similarly, TNA Discover also lists collections held by other repositories, such as the various English county record offices which often contain the papers of significant historical figures, including numerous Chief Secretaries and Lords Lieutenant. 

How do I interpret the sources?

The interpretation of surviving CSO records, as well as suitable replacements or substitutes, can be challenging. The inbox of the Chief Secretary and his staff was vast, with a mixture of official papers,reports, unsolicited letters from private individuals, and legal instruments such as King’s/Queen’s  Letters. Researchers must recognize that, before the twentieth century, the line between ‘personal’ and ‘official’ correspondence was often blurred. As such, letters which have a personal or political nature often contain significant information about official and administrative business within Dublin Castle, and vice versa.  Care must also be taken in distinguishing between such correspondence and surviving establishment lists, digests, internal reports, etc. Researchers are advised to consult the works listed below for information on the workings of the CSO during specific historical periods. 

Further reading
  • J.C. Sainty, ‘The Secretariat of the Chief Governors of Ireland, 1690–1800’, Proceedings of the Royal Irish Academy, 77 (1977), 1–33.
  • J.L.J. Hughes, ‘The Chief Secretaries in Ireland 1566-1921’, Irish Historical Studies 8–29 (1952), 5972.
  • Tom Quinlan, ‘The Registered Papers of the Chief Secretary’s Office’ (National Archives of Ireland, online resource).
  • R.B. McDowell, The Irish Administration 1801–1914 (Oxford, 1964).
  • Edward Brynn, Crown and Castle: British Rule in Ireland, 1800-30 (Dublin, 1978). 
  • Kieran Flanagan, ‘The Chief Secretary’s Office, 1853-1914: A Bureaucratic Enigma’, Irish Historical Studies, 24:94 (1984), 197–225.

  • Chief Secretary
  • Dublin Castle
  • Executive
  • Law and Order
  • Lord Lieutenant