| 16759 | Cashel, Ferns and Ossory Diocesan Archive (CoI) | | 1821-1836 | Wages Book, 1821-1836, place not clear, 1 volume. | Bolton Library Archive |
| 4270 | Church of Ireland Centre | Serial No37 | 1821 | General Correspondence, II:R. Forster to S. Bewley r... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 4271 | Church of Ireland Centre | Serial No46 | 1821 | General Correspondence, II:Miss Hawkshaw to D. Litto... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19004 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 20 - Miss Steele, to Model School ... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19008 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 34 - Extract of Minutes regarding ... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19009 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 35 - Extract from Proceedings of M... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19010 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 36 - Letter from M.A. McLoughlin r... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19011 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 37 - Report on the state of the Fe... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19012 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 38 - Letter to Committee from Sara... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19028 | Church of Ireland Centre | Box 36 | 1821 | Model School:Mod. 98 - List of twenty-six names bein... | Records of the Society for Promoting the Education of the Poor of Ireland |
| 19459 | Cloyne Diocesan Archive (RC) | Box D | 1821 | 1791.00/3/1821 Account of case between Mrs Baldwin ... | Bishop Copinger |
| 19460 | Cloyne Diocesan Archive (RC) | Box D | 1755
1821 | 1791.00/8/1821 Printed booklet Statutes of United D... | Bishop Copinger |
| 19444 | Cloyne Diocesan Archive (RC) | Box B | 1821 | 1792.06/3/1821 Letter. T R England, North Chapel, Co... | Bishop Collins |
| 3692 | Cork City and County Archives | U336/2 | 1821 | 'A Calendar of Prisoners in the custody of Henry... | |
| 23017 | Cork City and County Archives | U87/ | 1821-1830 | 5: Ten Annual Reports of the Charity School and an a... | Cork Presbyterian Meeting House Records |
| 22910 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 01: 9 January 1821 Doyle to Mrs Joseph, convent, Mou... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 23662 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 24: 1 June 1821 Archbishop Troy, Dublin to Doyle, Ca... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 23663 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 25: 2 June 1821 Bishop J. Murphy, Cork to Doyle, Car... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 23664 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 29: 3 June 1821 SC Propaganda to Doyle. Celebration ... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 23665 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 37: 12 July 1821 Mother Anne Lalor, Tullow to Doyle,... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 23667 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 70: Undated M. Mary A. Lalor, Convent, Tullow to Doy... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 24073 | Delany Archive | Box Bp/01 File JKL.1821/ | 1821 | 23: 26 May 1821 S. E.J. to Doyle at Carton. Doyle... | Papers of Dr James Doyle, Bishop of Kildare & Leighlin |
| 5096 | Irish Architectural Archive | 97/84/Box 62 | 1821-1840 | Account Book of Edward Conolly, 1821-1840, 1 item. | Castletown Papers |
| 5606 | Irish Architectural Archive | 94/136 | 1759-1821 | Collection of correspondence between Lady Louisa Con... | Connolly/Bunbury Letters |
| 12986 | Kilmainham Gaol Museum | 03MS-1B55-20 | 1821 | File on Mother Mary Aikenhead, regarding Butterly an... | |
| 1102 | Loreto Archives | Box 20.Z4 | 1821-1968 | Souvenirs, includes:Zaus - Loreto House in Australia... | |
| 23215 | Maynooth University and St Patrick's College, Maynooth | SH17 | 1737-1750
1821 | Collections of Historical and Various Subjects, volu... | Shearman Papers |
| 20165 | Meath Local Studies and Family History Department | Box C/ | 1821 | 22a Letter detailing expenses of lease, 1821 | Mountainstown Documents |
| 20226 | Meath Local Studies and Family History Department | Box I/ | 1821 | 35 Letter to Pollock, Mountainstown, 1821. | Mountainstown Documents |
| 8897 | National Archives of Ireland | M6933/10 | 1821
1822
1839
1840
1841 | Bundle of rentals of various portions of the Blake e... | Ballyglunin Papers |
| 11444 | National Archives of Ireland | | 1803
1821 | Letter from Custom Officials relating to the petitio... | Customs and Excise |
| 909 | National Library of Ireland | Ms5634 | 1805, 1821-1847 | Minutes of the management committee of the Collon, C... | |
| 1869 | National Library of Ireland | Ms19,785 (1-15) | 1821-1854 | See National Library of Ireland manuscript collectio... | Bruen of Oakpark (County Carlow) Papers |
| 2418 | National Library of Ireland | Ms9926 | c1821 | Commonplace Book of Lady Caroline Clements, c1821. | Leitrim Papers |
| 2744 | National Library of Ireland | Ms20945 | 1821-1938 | Nine letters from John D'Alton to his wife Kate, mai... | D'Alton Papers |
| 2868 | National Library of Ireland | Ms218 | 1821 | Copy of a play entitled 'Fitz-Gerald ou Le Comte de ... | |
| 2886 | National Library of Ireland | Ms1396 | c1821 | Typescript copy of a fragmentary census of Kilmore P... | |
| 2961 | National Library of Ireland | Ms8878 | 1816-1821 | Letters to Charles Brodrick, Archbishop of Cashel, f... | Brodrick Papers |
| 3046 | National Library of Ireland | Ms9971 | 1818-1821 | Expenditure Accounts of Michael and Helena Bellew, B... | |
| 3058 | National Library of Ireland | Ms10075 | 1821 | Costs of a marriage settlement, etc., Wade to Fox, 1... | |
| 3625 | National Library of Ireland | Mss12805-12807 | 1812-1821 | Accounts for rent of the Bohey, County Leitrim, esta... | Leitrim Papers |
| 9071 | National Library of Ireland | Ms14168 | 1821-1824 | Account Book of expenses on domestic goods and servi... | Grattan Papers |
| 9157 | National Library of Ireland | Ms14905 | 1821-1833 | Includes letters to Francis Moore from Catherine Bar... | |
| 9185 | National Library of Ireland | Ms15142 | 1774-1821 | Letters to Thomas Kemmis, Crown Solicitor, mostly on... | Kemmis Papers |
| 9544 | National Library of Ireland | Ms29785(3) | 1821-1854 | Recipe book of C.J. Connolly, 1821, continued by Mrs... | Bruen of Oakpark (County Carlow) Papers |
| 9691 | National Library of Ireland | Ms31918 | 1764-1821 | Rentals, rent acquittances, list of arrears, etc., r... | Bellew Papers |
| 9693 | National Library of Ireland | Ms31928 | c1780-1821 | Quit rent acquittances, accounts, etc., mostly relat... | Bellew Papers |
| 9710 | National Library of Ireland | Ms17911 | 1821-1893 | Letters and Papers of the Commissioners of Education... | Dr Michael Quane Papers |
| 10661 | National Library of Ireland | Ms16726 | 1819-1821 | Account and Wages Book of Charles King O'Hara, Annag... | O'Hara Papers |
| 10879 | National Library of Ireland | Ms21559 | 1821 | Letter to Eliza Crosbie, Liverpool, from her mother,... | |
| 19099 | Newry City Library | Q41.65.8 | 1801-1821
1911 | 14 volumes of bound, typescript and handwritten pape... | The Crossle Papers |
| 1816 | Public Record Office of Northern Ireland | D/2013 | 1817-1821 | This collection of the papers of W.S. Ferguson inclu... | |
| 6349 | Public Record Office of Northern Ireland | D/3263 | 1821-1947 | Records of Belfast Natural History and Philosophical... | |
| 7166 | Public Record Office of Northern Ireland | D/2995 | 1820-1821 | 3 arithmetic and exercise books of Elizabeth Stewart... | |
| 7878 | Public Record Office of Northern Ireland | T/1119/1 | 1821-1841 | Copy of a list of Stewarts in certain townlands in C... | |
| 8453 | Public Record Office of Northern Ireland | T/2728/1 | 1821-1858 | Copy of the Sunday register for the parish of Ardstr... | |
| 7180 | Public Record Office of Northern Ireland | D/3027 | 1821-1950 | The following is a selection of the material which i... | Galgorm Castle Papers |
| 7759 | Public Record Office of Northern Ireland | MIC/238 | 1759-1821 | Microfilmed copies of the Bunbury papers, 36 volumes... | Bunbury Papers |
| 7836 | Public Record Office of Northern Ireland | T/1022 | 1821-1851 | This collection includes genealogical notes on numer... | |
| 8600 | Public Record Office of Northern Ireland | T/450 | 1821 | Draft copy of Kilmore census returns, 1821. | |
| 8639 | Public Record Office of Northern Ireland | T/611/1 | 1821-1841 | Copies of extracts from the census returns for Count... | |
| 8652 | Public Record Office of Northern Ireland | T/658/1 | 1821-1851 | Copy of census extracts for County Londonderry, 1821... | |
| 8687 | Public Record Office of Northern Ireland | T/787/1 | 1821 | Copy of an extract from a census for County Antrim, ... | |
| 7857 | Public Record Office of Northern Ireland | T/1081/1 | 1472-1821 | Copies of notes on the Grierson family, Sweden, Scot... | |
| 7883 | Public Record Office of Northern Ireland | T/1126/1 | 1821
1831 | Copies of census extracts for Tamlaght-Finlagan, Ban... | |
| 7895 | Public Record Office of Northern Ireland | T/1156/1 | 1821 | Copy of a letter from Robert Peel, Whitehall, London... | |
| 8080 | Public Record Office of Northern Ireland | T/1692/2 | 1821-1917 | A family tree of the Bird family of Lackagh, Kilsker... | |
| 8213 | Public Record Office of Northern Ireland | T/2080 | 1821-c.1900 | This collection of 17 documents is comprised of copi... | |
| 8337 | Public Record Office of Northern Ireland | T/2460/1 | 1821 | Letter, with a copy, from Elizabeth Boardman, Port H... | |
| 8373 | Public Record Office of Northern Ireland | T/2553 | 1821-1947 | This collection of c20 documents includes, for examp... | |
| 8490 | Public Record Office of Northern Ireland | T/2830 | 1821-1825 | Copy of a volume of correspondence from Doctor John ... | |
| 8518 | Public Record Office of Northern Ireland | T/2938 | 1821 | Copy of a letter from Mrs Watt to Catherine Hutton c... | |
| 8595 | Public Record Office of Northern Ireland | T/425/ | 1821 | T/425/1 and T425/4 2 copies of population returns fo... | |
| 8638 | Public Record Office of Northern Ireland | T/607 | 1821-1841 | Copy of an extract from the census returns in Record... | |
| 8666 | Public Record Office of Northern Ireland | T/715 | 1758-1850
1821 | This collection includes the following: A copy of a ... | |
| 8710 | Public Record Office of Northern Ireland | T/889 | 1816
1821 | This collection includes the following: Copies of no... | John Elliott and Johns Solicitors Papers |
| 655 | Religious Society of Friends in Ireland Historical Library | YM/B15 | 1757-1821 | Women's Meeting: Epistles and rules of discipline fo... | Yearly Meetings |
| 1346 | Religious Society of Friends in Ireland Historical Library | Deed Box XIII | 1821-1950 | Elizabeth Beale married to William Beale, merchant o... | Deed Boxes, Miscellaneous, New Shelf Head Lists |
| 4152 | Religious Society of Friends in Ireland Historical Library | Deed Box XIII/Folder 6:6 | 1821 | Elizabeth Beale: Married to William Beale, merchant ... | Deeds |
| 24979 | Royal Irish Academy | | 1821
1929 | Catalogue of Irish Manuscripts in the Royal Irish Ac... | |
| 22510 | Royal Society of Antiquaries of Ireland | | 1821-1835 | Corporation of Weavers, Admission, 1821-1835. | Records of the Corporation of Weavers |
| 22515 | Royal Society of Antiquaries of Ireland | | 1821-1837 | Book of Brothers, 1821-1837. | Records of the Corporation of Weavers |
| 6895 | Trinity College Dublin, Manuscripts and Archives Department | TCDMs5109 | 1821-1847 | Autograph Album of poems and drawings kept by Anne F... | Arnold family |
| 10238 | Trinity College Dublin, Manuscripts and Archives Department | TCDMs10532 | 1816
1821 | Manuscript notes and printed excerpts relating to th... | William Mason Monck Papers |
| 11201 | Trinity College Dublin, Manuscripts and Archives Department | V119/a-b | 1821-1825 | Correspondence of Viscount and Viscountess Stopford ... | Courtown Papers |
| 18593 | University of Limerick Special Collections and Archives | P20 | 1821-1931 | 2 boxes (75 files).A. Family History (1910-1931)B. J... | The Barry Collection |
| 23327 | Waterford City Archives | P9/ | 1821 | 1: Manuscript notes taken from 1821 census returns v... | Canon Power Papers |