From the late eighteenth century a police force operated in Dublin city, with a part-time, ad hoc constabulary in the rest of the country. In 1814 the armed Peace Preservation Force was created, followed in 1822 by the full-time County Constabulary. These two were amalgamated in 1836 to form the Irish Constabulary, renamed the Royal Irish Constabulary (better known as the RIC) in 1867. The separate Dublin force remained in existence and was known as the Dublin Metropolitan Police (DMP). With the creation of the Irish Free State in 1922, the RIC was disbanded. Responsibility for policing passed to the Garda Síochána in the 26 Counties and to the newly formed Royal Ulster Constabulary in the six counties of Northern Ireland..
Excellent personnel records were kept from 1816. The General Register from that date to 1922 is now in the National Archives, Kew (HO 184), with microfilm copies in NAI, the LDS Family History Library and PRONI. For each recruit it includes a brief service record, a date of marriage and wife's native county, and the name of the individual who recommended him. This can be important in helping to identify an exact place of origin, as the recommendations usually came from local clergymen or magistrates who knew the recruit personally. Thom's Directories can pinpoint their address. HO 184 also includes a separate Officers' Register. Both the Officers' and the General Service Registers are now transcribed and imaged at FindMyPast.ie, along with pension records and other RIC-related material..
To use the microfilm copies, Jim Herlihy's The Royal Irish Constabulary : a complete alphabetical list of officers and men, 1816-1922 (Dublin: Four Courts, 1999) is essential. The registers are purely numerical and Jim's book supplies the Service Number for every recruit and cadet.
A further source at the National Archives, Kew, is PMG 48, 'Pensions and allowances to officers, men and staff of the Royal Irish Constabulary and to their widows and children'. This dates from the 1870s and usually gives the address of the recipient. It is online at Ancestry.com also at FindMyPast.
An online discussion forum is at www.irishconstabulary.com.
The DMP register is now held by NAI and is available on microfilm. It does not give marriage details, but supplies a parish of origin. Jim Herlihy's The Dublin Metropolitan Police: A short history and genealogical guide, (Dublin, Four Courts, 2001) reproduces all of the information in the DMP register. The first 252 pages of the register are imaged at digital.ucd.ie/collections.