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Have an O'Reilly in your family tree? It's likely you've roots in County Cavan! This week genealogist and historian Michael McShane along with data scientist Catherine Kerr chat all things County Cavan and give us an overview of their comprehensive website that focuses exclusively on Cavan records. If you've roots in the County, it's a must-read.

County in Focus: Cavan

Clogh Oughter Castle, (pictured below) located on a small island in Lough Oughter, was the stronghold of the O’Reilly clan from the mid 13th century up until around 1600. The O’Reilly name is synonymous with Cavan. It is derived from the noble ‘Breifne Uí Raghallaigh’ clan who ruled the kingdom of Breifne. The region is named after the Uí Briúin Bréifne, a clan who originally came from north Roscommon. The original Masraighe and Cathraighe tribes were absorbed into the Uí Briúin tribe. The kingdom of Breifne essentially covered the area we now know as the counties Leitrim and Cavan. West Breifne, which lies predominantly within county Leitrim, was ruled by the O’Rourke clan and included what we now call the baronies of Tullyhaw and Tullyhunco in Cavan 

Clogh Oughter Castle

Fig.2. Clogh Oughter Castle

The O’Reillys and the O’Rourkes

The O’Reillys and the O’Rourkes were constantly at odds with each other and a major battle, known as the Battle of Maigh Sleacht, took its toll on both sides ending in an undecisive win of sorts for the O’Reillys. This conflict significantly weakened both sides and ultimately culminated in the division of the kingdom in 1256 into east and west Breifne. East Breifne or Breifne O’Reilly came under the O'Reilly’s control and they ruled the region from the 12th to the 17th century. The county took its present boundaries in 1579 when East Breifne was renamed Cavan, after Cavan Town, and was shired into Ulster.

After the Flight of the Earls in 1607, the six escheated (confiscated) counties of Ulster which comprised Armagh, Cavan, Donegal, Fermanagh, Derry and Tyrone came into the hands of the Crown. The process of plantation began in 1608 when plans were drawn up for the granting of these counties to the various entities who were in the favour of King James I. The 1609 maps provide the historian with a unique time-capsule which can be used to trace back and link some of the earliest townland names to their present day counterparts. No set of maps at this scale of detail pre-exists for the counties covered. It is the baseline for the cartographic study of the townlands which were fortunate enough to have been included in the process.


Detail from the 1610 Bodley map (pictured below) of the Barony of Tullyhunco showing the individual townlands which were to be granted to the Scottish undertaker Alexander Achmootie in the newly created Estate of Dromheada. Reference numbers in red indicate townlands which still exist today.

1610 Bodley map of the barony of Tullyhunco

Fig. 3 Detail from 1610 Plantation Map

County Cavan Lands

We are fortunate that the troubled history of County Cavan has resulted in the creation of a very large amount of survey and land ownership information which would otherwise not exist. Our colonisers certainly knew how to keep records when it came to the confiscation, plantation and taxation of lands. The six escheated counties of the province of Ulster became one of the best mapped and surveyed parts of the world, particularly in the seventeenth century, when the ownership of lands went through multiple hands before settling down into the relatively quieter period of the eighteenth century. You can read the guide to the seventeenth century surveys of Cavan here.

Townland map of the parish
Fig. 4 Townland map of the parish of Annagh showing the ownership of the lands at the time of the Commonwealth c. 1652

Top 20 Surnames of County Cavan in 1901 and 1911

Surname 1901 Count 1901 Rank 1911 Count 1911 rank
Reilly 5532 1 4874 1
Brady 3590 2 3421 3
Smith 3484 3 3620 2
McGovern 2149 4 2092 4
Lynch 2041 5 1914 5
Smyth 1704 6 1375 7
Clarke 1570 7 1461 6
McCabe 1374 8 1304 8
Maguire 1256 10 1009 13
Fitzpatrick 1215 11 1091 10
Farrelly 1187 12 1070 11
Dolan 1130 13 1039 12
Donohoe 906 14 895 14
Galligan 854 15 768 15
Gaffney 601 16 533 17
Martin 579 17 540 16
Coyle 527 18 479 19
Fitzsimons 521 19 458 20
Johnston 499 20 456 21
Murray 493 21 516 18
Carolan 487 22 447 22

Some prominent surnames of Cavan

With commentary from Irish Families by Edward MacLysaght, first published in 1957.

Brady - MacLysaght says: The MacBradys were a powerful sept belonging to Breffny, their chief holding sway over a territory lying a few miles east of Cavan town. The Four Masters record many illustrious chiefs of the name there. In 1256 reference is made to the death of Tighearan MacBradaigh in a battle against the neighboring O’Rourkes. The historian Abbé MacGeoghegan says that the MacBradys are a branch of the O'Carrolls of Calry, Co. Leitrim, a statement which has been often repeated, but modern authorities refute this. In any case they have always been pre-eminently associated with Co. Cavan; and it is in Co. Cavan and adjacent areas the Bradys are mostly found to-day. They are indeed very numerous in Ireland with an estimated population of nearly 10,000 persons so called. Originating from Mac Bradaigh, son of Brady, is a very prominent Cavan Name. The earliest recorded namebearer was Gilbert MacBrady, the bishop of Ardagh from 1396 to 1400. 

McGovern/Magauran - The Magaurans, or McGoverns, are anglicized versions of the Gaelic surname Mac Samhradhaín.. MacLysaght says that the eponymous ancestor was Samhradhan, who lived circa 1100 at the time surnames came into being. This man was descended from Eochadh (fl. eighth century) whence the territory of the MacGoverns or Magaurans was called Teallach Eochaidh now Tullyhaw, in north-west Cavan. There is a village called Ballymagauran in that area. The leading families of the sept were allied by marriage to the Maguires, O'Rourkes and other powerful families of Cavan and are frequently mentioned in the Annals during the thirteenth to sixteenth centuries. Ballymagauran in Tullyhaw was burned by Maguire in 1481 for an allegedly dishonourable act by the Magauran of the day. "The Book of the Magaurans" is one of the famous old Gaelic manuscripts.

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MacCabe - The MacCabes came from the western isles of Scotland about the year 1350 as gallowglasses to the O'Reillys and the O'Rourkes, the principal septs of Breffny. They became themselves a recognized Breffny sept, their chief being "Constable of the two Breffnys". Modern statistics show that they are still much more numerous in the Breffny area than anywhere else. As landed proprietors they were as much associated with Co. Monaghan as with Co. Cavan; however the principal families of MacCabe lost their estates in the Catholic débâcle after the battle of Aughrim in 1691.

Ó Cléirigh/Clery/Clarke - The name probably derived from the word cleireach meaning a clerk or cleric. The Ó Cléirigh clan, also known variously as Clarke, Clark, Clerke, Cleary, Clery, Clerkin, O’Cleary, and O’Clery were an ancient tribe from South Connaught who were scattered in the 13th century when the Normans invaded and conquered their territories. The branch which settled in Cavan has almost disappeared, at least as Clery, although the Clarke version has survived and is fairly common today. One account states that the Ó Cléirigh name is one of the oldest in Europe dating back to AD 916, and descends from the Uí Fiachrach, who like the Uí Briúin, are also a sept of the dynasts of the sons of Eochaid Mugedón, a 4th Century high king of Ireland. After losing their lands, branches of the clan settled in Mayo, Cavan and Kilkenny. There was a particularly strong concentration of Ó Cléirigh families in the Bailieborough area where their descendants still reside.

O'Reilly, (O'Rahilly) - O'Reilly, in Irish Ó Raghailligh, i.e. descendant of Raghallach, was until recently much more commonly found without the prefix 0. Reilly and O'Reilly constitute one of the most numerous names in Ireland, being among the first dozen in the list. The bulk of these come from Cavan and adjoining counties, the area to which they belong by origin, for they were for centuries the most powerful sept in Breffny, their head being chief of Breffny-O'Reilly and for a long time in the middle ages his influence extended well into Meath and Westmeath. At the present time we find them very numerous still in Breffny, heading as they do the county list both in Cavan and Longford. In 1878 O'Reilly landlords possessed over 30,000 acres.

(O)Sheridan - The Sheridan family originated in Co. Longford, being erenaghs of Granard, but later moved to the next county Cavan where they became devoted followers of the powerful O'Reillys. The name is Ó Sirideáin in Irish, i.e. descendant of Siridean, a personal name the derivation of which is uncertain. While Cavan is the county in which they are still to be found in greater numbers than elsewhere, the Sheridans are now dispersed widely throughout every province, though less in Munster then elsewhere. The prefix O has been entirely dropped since the seven- teenth century. The Sheridans have been chiefly notable for their achievements in the literary field. The most famous, of course, was Richard Brinsley Sheridan (1751-1816) the Dublin-born dramatist and orator, long a prominent member of the English parliament; his mother Frances Sheridan (1724-1766), was also a successful writer, as was his brother Charles Sheridan (1750-1806); and yet another member of this remarkable literary family was Thomas Sheridan (1719-1788) who was also one of the leading actors of his day.

Smith - MacGOWAN, O'GOWAN, Smith, (MacGuane) Irish surname MacGowan (not to be confused with the Scottish MacGoun) is more often than not hidden under the synonym Smith. In Irish it is Mac an Ghabhain, i.e. son of the smith, and its translation to Smith (commonest of all surnames in England) was very widespread, particularly in Co. Cavan where the MacGowan sept originated. It is included by the chroniclers as one of the principal septs of Breffny. On the borders of Breffny, in Co. Leitrim, and to the north west in Counties Donegal and Sligo, the true form in English, MacGowan, is still used in preference to Smith. There was, too, in east Ulster a distinct sept of O'Gowan, a name which was also anglicized Smith. A very prominent member of this family, long resident in Co. Cavan, has recently, with the full approval of the Irish Genealogical Office, resumed the name O'Gowan. They came originally from a place called Ballygowan in Co. Down. O'Gowan is very rarely met with in modern times. It is, however, to be found in the census of 1659 as one of the principal Irish names in the counties of Monaghan and Fermanagh.


Searching for your Cavan ancestors

The importance of the townland cannot be emphasised enough. The identification of the ancestral townland for the purposes of genealogical and historical research is critical in terms of confirming that you have the correct individual and all the information that follows from that. The townland is the smallest cadastral unit which can be traced back to medieval times. For centuries, the prevailing land denomination in Co. Cavan was the Poll, a land measurement unit which still exists to this day in the form of townlands. County Cavan is made up of just over two thousand townlands. You can imagine these townlands as a patchwork quilt of plots of land which combine to cover the entire county. Cavan’s townlands are distributed among the 36 civil parishes which also form an important part of the organisational element of the administrative record keeping system.

Cavan Townlands

 Fig. 5 The patchwork quilt of Cavan’s 2,000 townlands distributed throughout the 36 civil parishes of the county.

Once the specific townland is established the doors to research are unlocked as ultimately all Crown records and church records use the townland as the lowest level of identification of place. The search can then be extended into estate records, maps, deeds and newspaper articles to name but a few. 


Armed with the townland you can now proceed to to explore the available information which is all free to view. The site has undergone significant development since it was first launched in 2015 and now holds the entire available record set of all surviving census and census substitute listings for the county from 1821-1911. A considerable challenge was the re-indexation and correction of the records which are presented on the National Archives census search engine. A substantial portion of the available data set were found to be concealed or mis-catalogued behind the search interface and this often results in incorrect returns. This work has been documented in a number of articles which have been published in Breifne. We believe that the most reliable way to navigate the census records is now via 

Cavan Townland Links

Cavan Community on IrelandXO

With over 1,000 registered members with roots in County Cavan, it's a vibrant space on the IrelandXO website. Some of the lastest ancestor profiles include Peter Hartin born in 1850 in the civil parish of Scraby, Samuel Heaslip born in Denn, County Cavan, Mary Brady born in Larah in 1862 and Jane Leahy born in Ballymachugh in 1826. It's easy to search the Cavan database, just choose 'Cavan' and enter your family name to see if you find any matches!


Summary of Records available to view by Townland

The 1901 and 1911 census records have recently been added to the search facility. These have been indexed by townland and this allows, for the first time, the presentation of all the available records for each of Cavan’s 2,000 townlands in one easy to navigate location. We have also developed a new search engine which allows our users to locate an individual from the complete set of 345,000 records and a guide to carrying out a search was given in our online talk of 26th April 2022 which can be viewed on the Cavan Library website.

A search by townland will produce the following results in one location:

  • Location map and basic townland information along with specific articles relevant to the townland where available.
  • 1609 Bodley plantation map analysis for Kildallan, Killashandra and Scrabby townlands. 137 townlands have been identified and classified.
  • 652 Commonwealth survey data and maps for all parishes. Proprietor name for each townland is provided along with estate maps. c.1,500 unique records including some tenant names.
  • 1821 Census of Cavan. The records cover 17 of the 36 civil parishes of county Cavan and list c.80,000 individuals. This is a very rare surviving record set as nearly the entire census for the whole country was lost in the fire of 1922 in the Four Courts.


1821 Census Records Cavan

Fig. 7 Map showing surviving 1821 census records for Cavan

  • 1830 Tithe Applotment records for 35 of the 36 civil parishes. Re-indexed, corrected and presented in searchable tabulated form for ease of access. Tenant names are provided. c.30,000 individual records are available to view here.
  • 1836 Name Book records for the townlands of 9 parishes first published in The Heart of Breifne 1979-1987.
  • 1841 Census of Killashandra. Cross checked, corrected and fully searchable data set. c. 15,000 individual records.
  • 1865 Griffith’s valuation records. Covers the entire of County Cavan. Tenant names are provided.
  • 1901 census. The 1901 records for Cavan contain 97,437 individual records. The NAI website search by townland does not take into account issues we have identified with older name versions, misspellings and incorrect transcriptions which we believe may conceal c.50% of searches carried out by townland name. We have rectified this issue here by re-indexing the entire dataset in accordance with the approved townland categorisation.
  • 911 census. The 1911 records for Cavan contain 91,343 individual records. Same issues apply as per 1901 record set.
  •  All included townland records have been referenced to their official Logainm identifier. is the official database of Irish placenames

About the Author

Michael and his wife Catherine host and have worked extensively on compiling and correcting census and census substitute records for Cavan. Although not a native of Cavan, Michael has traced his ancestors back to the townland of Cloggy in the parish of Killashandra. Michael is an architect living in Killiney, Co. Dublin and has a keen interest in cartography. This passion for maps is reflected in the content of Catherine brings her experience as a data scientist to compiling and presenting the data encountered into an easily accessible layout. 

Michael has written a number of articles for Breifne, Journal of Breifne Historical Society, which may be useful to anyone with an interest in Cavan history and genealogy.

They include:

  • ‘Bodley’s map of Tullyhunco, 1609’ in Breifne, 13:50 (2015), pp 498-535. Read on-line here 
  • ‘Land “parcells” of Tullyhunco from the Ulster inquisitions of 1629’ in Breifne 13:51 (2016), pp 756-780 
  • ‘“A very curious survey of the county of Cavan”. The Commonwealth survey of 1652-53. Part 1, West Cavan’ in Breifne 13:52 (2017), pp 19-90. Read more here
  • ‘“A very curious survey of the county of Cavan”. The Commonwealth survey of 1652-53. Part 2, East Cavan’ in Breifne 14:53 (2018), pp 329-384 
  • ‘Guide to seventeenth-century surveys of Cavan as a source for townland studies’ in Breifne, 14:54 (2019), pp 436-455. Read on-line here
  • ‘Robert Craige’s County Cavan tenants, 1703-4: an update’ in Breifne, 14:54 (2019), pp 456-468. 
  • ‘Cloggy, a Cavan townland, 1609-1911’ in Breifne, 14:55 (2020), pp 621-688. Read the article here 
  • ‘Tithe Applotment Books: navigating the National Archives online records’, in Breifne, 15:56 (2021), pp 46-60. Search the records here
  • ‘The destruction of the Public Record Office in 1922 and the surviving census and census substitute records of county Cavan 1821-1911’ , in Breifne, 15:57 (2022), pp 287-298. Watch the on-line talk here

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