Update March 2022

Study Purpose

To promote knowledge and understanding of the Cosgrove surname to include its origins, meanings, variants, frequency, and distribution as well as provide support to family historians and genealogists in the research of their Cosgrove family lines. 

Study Vision

Provide a forum that 1) promotes knowledge and understanding of the Cosgrove surname; 2) enables family historians and genealogists to network, collaborate, and advance research into their Cosgrove family lines; 3) provides advice to researchers on where to find quality records and other pertinent information about the surname or their Cosgrove families, and 4) promotes the ethical use of Y-DNA and autosomal DNA testing to connect Cosgrove cousins together and to support their genealogical research goals.

Note: see the familytree.com article on the difference between a family historian and genealogist: https://www.familytree.com/blog/the-differences-between-a-genealogist-and-a-family-historian/

Study Goals

I have five main goals for the one-name study:

1) Support and advance members' research into their Cosgrove family lines. We offer advice on research techniques and records collections to examine, provide updates on new records collections as they are released onto government and commercial websites, and maintain a collection of records and databases that may be of use to family historians.

2) Connect Cosgrove cousins together through genealogical research and/or DNA testing (Y-DNA and autosomal DNA testing).  We support this goal primarily by facilitating engagements among members at our DNA projects at Family Tree DNA and our Facebook Group.

3) Offer advice to members who are considering using DNA testing to support their genealogical research. This includes members who have not conducted any DNA testing to date as well as current members who are deciding whether to upgrade existing test results or expand DNA testing to other family members.

4) Promote the study of the origins and meaning of the Cosgrove surname and its variants. This includes gaining a clear understanding of the surname's origins and distribution in Ireland, Northern Ireland, and Great Britian as well as determining how the name's origins in each listed country is connected (or not) to the name in the other countries. These countries were specifically chosen because initial research suggests the Cosgrove surname has a mix of both English and Irish origins.  The name "Cosgrove" is clearly English in origin.  However, English authorities Anglicized the Gaelic family name of Coscraigh to Cosgrove in the 1500-1600s.  Over the coming years, I want to be able to identify and distinguish the Irish Cosgrove families from English Cosgrove families to gain a better understanding of the name's origins, its frequencies and distributions, and to add clarity for family historians and genealogists on the origins of their respective family lines.

5) Promote research into the Ancient Irish Dynasties that either included a Clan Coscraigh and/or had a prominent member named Coscrach (or Coscragh) listed in their pedigrees. Optimally, we would like to use Y-DNA testing and traditional research methods to confirm the existence of the Coscraigh Clans and the approximate locations of each Clan's territories. My hypothesis assumes that concentrations of Cosgrove families in specific geographic locations on the Isle of Ireland during modern periods (1700s-present day) likely mirror the Ancient Coscraigh Clans' territories. If this is proven true, it would strongly suggest these modern Cosgrove families are descendants from the Coscraigh Clans that once lived on the exact lands. This could potentially help families in re-connecting their Cosgrove lines back to ancestral areas within Ireland, which is critical for descendants of Irish immigrants who may not know where their families originated back in Ireland. These insights could help focus a member's research to a specific county or group of counties as opposed to having to research records from across the entire country. 

Study Approach

Managing a study of the size of the Cosgrove surname study requires a deliberate and logical approach.  Since my initial research findings suggest the majority of people today who carry the surname or one of its variants either live in or can trace their Cosgrove family lines back to Ireland, Northern Ireland, England, Wales, or Scotland, I plan to begin my research in the British Isles.  My approach consists of six steps, some of which will be conducted simultaneously while others will be conducted sequentially. As of March 2022, I am currently focused on Step 4.a., Step 5, and Step 6, and will be for the foreseeable future: 

Step 1: Identify and analyze the Cosgrove surname's meaning (initial research completed but under refinement).

Step 2: Identify and analyze the Cosgrove surname's origin(s) initial research completed though updates are likely to occur over time as new information is discovered and validated).

Step 3: Identify and analyze the Cosgrove surname's distribution and frequency at the country, regional, and global-levels (on-going; will be updated periodically based upon researching findings discovered during during Step 4).

Step 4: Identify,  research, analyze, and as time permits, re-construct, Cosgrove family units in Ireland, Northern Ireland, England, Wales, and Scotland from the earliest records to present day.  This will include the collection and analysis of birth/baptism, marriage, and death records; land records; military records; wills; obituaries; cemetery records; and census and other government records.   My intent is to build databases of pertinent information to enable the reconstruction of family units, specifically from the 1700s-early 1900s.  The family groups will be organized at the County-level.  The records and information collected should enable descendants of the Irish Diaspora and descendants of British immigrants with Cosgrove family lines to trace and reconnect their modern families back to their ancestral lines.   

a. My initial efforts are focused on Ireland, Northern Ireland, and Scotland thru 2022-2024.

b. Once I complete my research of these three countries, I plan to research records collections in England and Wales in 2024-2026.

c. Once I complete my research of English and Welsh records, I plan to research records collections in the United States, Canada, Australia, and New Zealand; this phase of research will likely begin in earnest after 2026.  This step will include attempting to re-connect Cosgrove families back to their countries of origin using the records and information collected and collated during Steps 4.a and 4.b.  Considering the significant number of Cosgroves who immigrated to other parts of the world over the centuries, I will likely be on this step until my last breath on earth.

Step 5: Manage the Cosgrove Surname Project (DNA specific) at Family Tree DNA (continuous requirement).

Step 6: Manage the Cosgrove Surname Project Group on Facebook and the one-name study's blog/newsletter (continuous requirement).

Background and Inspiration for the Cosgrove Surname Study

The origins of the surname study was inspired by my desire to expand upon the surname project I started at Family Tree DNA in April 2016.  I decided to establish the Cosgrove Surname Project at Family Tree DNA  as a way to bring together genetic genealogists researching their respective Cosgrove lines.  At the time, I was facing a significant brick wall in my own research into my Cosgrove family and was struggling to find quality records pertinent to my family.  I turned to both Y-DNA and autosomal DNA testing to collect additional data and insights with the goal of better focusing my research efforts. 

Along with my DNA results, I received some invaluable assistance from total strangers in pointing me to other sites and records collections for my consideration.  Without their support and advice, I would likely not have had success in finding my ancestral roots in County Limerick, Ireland.   While I was ultimately rewarded by my journey, it was nonetheless frustrating and challenging....more so than it needed to be.   I started the surname project in hopes of helping others achieve their genealogical research goals while minimizing the frustrations and challenges I experienced. 

As the founding project administrator, I wanted to promote the ethical use of Y-DNA and autosomal DNA tests to help family historians and genealogists connect with Cosgrove cousins.  I also wanted to ensure the project was inclusive and not exclusive.  So, I opened the DNA project  not only to Cosgroves, but also to people whose family trees included lines that carried the surname's variants such as Cosgriff/e, Cosgrave, Coskery, Coskrey, etc.

Family Tree DNA and its project members expect their surname project administrators to be experts on the surname.  Specifically, project members expect their administrators to know the geographic and historical origins of the sponsored surname, its frequency, and its variants as well as the Y-DNA signatures of the different genetic Cosgrove families.  When I started the surname project, I was far from an expert.  However, I was committed to becoming one.  I dove headfirst into a sea of historical books and academic journals that discussed the origins and meaning of the Cosgrove surname, the Coscraigh clans of Ancient Ireland, and modern Cosgrove families and personalities.  I learned quite a bit about the surname as well as the amount of effort and time it took to find, read, and comprehend quality and reputable information.  Despite my dedicated studies over the last six years, I still don't think I have even scratched the surface of what there is to know about the Cosgrove surname.

One of the challenges I and others have had is finding reputable and quality information about the Cosgrove surname and the families that carry it.  When I would discover relevant records and information, I struggled with finding an effective way to share the information I had collected with other interested parties.  While FTDNA's project sites are great for managing DNA requirements, they are much less effective as platforms for sharing information.  Plus, not every genealogist has the desire to take a DNA test for a variety of reasons, so the FTDNA project was only targeting a very tiny audience.  I needed to expand my reach to my perspective audience(s).   I eventually established a group on Facebook to act as a sister page for the FTDNA project.  The Facebook page provided people who didn't have a desire to take a DNA test (at least initially) a forum to participate in the surname project.  Again, while Facebook is great for informal, short discussions, its not optimal for sharing and storing large quantities of information.

My natural progression led me to establish a one-name study for the Cosgrove surname and its variants here at the Guild of the One-Name Studies.   The Guild provides an excellent platform for me to share relevant information regarding the surname.  It also allows me to link a blog I started a year ago to its site.  I hope that I can reach as many people as I can through the combination of the Facebook page, DNA project, blog, and one-name study to promote the surname and inspire people to successfully research their own Cosgrove family lines.  Since establishing and linking the four forums together under one umbrella, my membership in the surname project has expanded from 26 members in January 2017 to 108 by the end of 2019.  As we entered 2022, we reached over 230 members.  

I hope you find this one name study and its blog (https://cosgrove.one-name.net/) both informative and helpful.

Contact information: Please send any queries or information to cosgrove@one-name.org.

- Primary variants: Cosgrave, Cosgriff, Cosgriffe, Coskery, Coskerry, and Coskrey.  See Note 1 below.

- Other surnames that may be used as variants: Mc/Mac/Cusker, Mc/Mac/Cosker, Mc/MacOscar, Mc/Mac/Osker, Coskeran, Cuskeran, and Coscoran.  See Note 2 below.

- Less frequently used variants and possible deviants: Cosegrove, Cosegrave, Coscor, Causgrove, Causgrave, Cosgrive, and Cosgreve

Note 1: It is likely that authorities used a variety of spellings to replace the Gaelic family name of Coscraigh, resulting in the establishing of the Cosgrove, Cosgriff, Cosgrave, Coskrey, and Coskerry surnames.  While some Anglicized surnames may have been chosen due to how similiar they appeared to the Gaelic name (Cosgrove and Cosgrave vs Coscraigh, Coscragh), other Anglicized surnames may have been selected (or spelled) based on phonetic similarities (Coskrey and Coskerry vs Coscraigh (Cos - cray).

Note 2: There appears to be instances, whether properly or improperly, where the surnames Cosgrove, McCusker, McCosker, and McOsker may have been used as variants for one another during the Anglicization of Gaelic surnames during the 1500-1600s.   While a clear explanation does not exist the crossing of surnames occurred, it is plausible that authorities may have used the English name Cosgrove as a variant for the Gaelic names Mac Giolla Coscair, Mac Oscair, O' Coscair, etc. (in addition to McCusker, McCosker, and McOsar/McOskar) based on similarities in phonetic sounds and spellings. 

Two DNA project currently exists at Family Tree DNA of interest for our surnames: one for the Cosgrove surname and its variants and another for the McOsker-McCusker family that descends from the Mag Uidhir of County Fermanagh  (https://www.familytreedna.com/groups/mcosker/about) .  Ken McOsker, the primary project administrator for the McOsker-McCusker DNA project, has also established a dedicated website (http://mcosker.com) that provides background on the McOsker surname origin. 

A small number of Y-DNA results do show a genetic connection among some men who carry the Cosgrove and McCusker surnames.  The men who share these close genetic connections have traced their respective surname lines back to specific regions in northern Leinster and Ulster provinces (see the Y-DNA section below).   Currently, a One-Name Study does not exist for the McOsker-McCusker names.  Until one is established, we will be happy to help family historians and genealogists with their research of these names until such time a study is established.  Until then, we are actively researching the genetic and genealogical connections between our two surnames.

People often ask me what the ethnicity of my “Cosgrove” name is.  When I tell them it’s Irish, they immediately tell me it can’t be.  When I ask them what they thought it was, they usually tell me they couldn’t figure it out, hence why they asked me the question.

To be fair, “Cosgrove” is actually an English name.  According to Ancestry.com (https://www.ancestry.com/name-origin?surname=cosgrove) , Cosgrove is derived from an Old English name “Cof” and another Old English word “graf” for grove or thicket.  An English village by the name Cosgrove exists in Northamptonshire, England.  The village was first referenced in Domesday Book in 1086, about 20 years following the Norman invasion of England.   The village's name is likely the original source of the word the English authorities used as a replacement for the Gaelic name Coscraigh when they Anglicized Gaelic surnames in Ireland in the 1500s-1600s.

The Gaelic name O' Coscraigh, which means "descendant of Coscragh." Mac Coscragh means "son of Coscragh." The name Coscragh  is derived from the term coscur or cosgar meaning “victory” or “triumph,” or simply put, victorious.  It is sometimes translated to mean "slaughter" in the context of warfare.  Other common Gaelic spellings for the name include Coscradh, Coscrach, Cosgraidgh, MacCosgraig, Choscraig, Coscair, Coscraig, Chuscraid, Choscair, O’Coscrachain, and O’Cosgraidhe.  Other spelling variants likely exist.  I cannot determine why each historian has chosen to spell the name differently other than based on their personal preferences, understandings, or proficiencies (or combination) of Old Irish/Gaelic language as well as the natural evolution of spellings of names that occurred over the centuries.  

My personal interpretation of various lineages of the Ancient Irish Clans indicates that the name Coscragh have been used as an adjective along with a personal name.  For instance, in Reverend Geoffrey Keating's The History of Ireland, Vol III, Crimthann Coscragh, who lived in the 2nd Century BC,  is listed among the lists of High Kings of Ireland.  One can translate his name as "Crimthann the Victorious," likely the result of his victories in battle.  This the "earliest" use of the name (albeit adjective) that I found during my examination of various historians' works and translated versions of Ancient Irish Annals.  Later pedigrees and entries in the Irish Annals show the adoption of the adjective as a personal name and later a Clan name.

As of March 2022, my research into Ancient Irish Clans has led to the discovery of 23 Dynasties and Tuaths that either had a recorded Clan Coscraigh among its clans and/or had a prominent person named Coscragh recorded in their pedigrees.  The picture below depicts the name and locations in Ireland of the Coscraigh Clans' territories (I was granted permission from the map's creator, Dennis Walsh,  to use his Irish Clan map as the underlying map for my analysis: http://sites.rootsweb.com/~irlkik/ihm/ ).

Based upon my analysis of the number and location of the various Coscraigh Clans from the 500-1100s AD, I believe that the modern geographic distribution of Irish Cosgrove families, especially from the 1800's, correlate in part to the Ancient Coscraigh Clans' territories.  The heat map below depicts the parish and civil district locations with recorded Irish Cosgrove baptisms and births, respectively, from the 1700s-early 1900s.  As one can see, some of the concentrations of baptism and birth locations mirror the geographic locations of some of the Coscraigh Clans' territories to varying degrees:

As of March 2022, I have not yet identified any English Cosgrove families of pure English origins.  Many of the English Cosgrove families I have discovered thus far appear to have Irish origins. 

The United States by far has the largest population of the Cosgrove surname than any other country according to 2014 data (source: https://forebears.io/surnames/cosgrove#place-tab-2014).  This is likely because of the large number of Irish immigrants to migrated to the United States during the 1700s-1900s.  The following map and graph show the surname's distribution across countries:

As discussed in the Study Approach above, I want to be able to help family historians and genealogists re-connect their modern Cosgrove family lines back to their ancestral family likes and locations.  One of the research objectives is to collect relevant birth/baptism, marriage, and death records in hopes of being able to accurately reconstruct family units from the 1700s-early 1900s that lived in either Ireland, Northern Ireland, or Great Britain.   Two techniques I am using are building databases and heat maps to graphically display the distribution of recorded occurrences of births and baptisms (and eventually marriages).  Below are two examples of birth and baptism heat maps for the island of Ireland and Scotland that depict the geographic location of births from the 1700s-early 1900s (predominately from the 1800s):

(Being updated as of March 2022).

While we use Y-DNA results to identify genetic matches among our project members, we hope to use the Big Y 500/700 results to help confirm the Y-DNA signatures of the various Ancient Irish Cosgrove Clans.  While we lack sufficient number of Y-DNA results to draw any reasonable conclusions with a high degree of confidence at this stage, we do believe we will be able to begin identifying the SNP signatures of some of the Clans within the next few years.  Specifically, we may be on the cusp of identifying the unique family SNPs for descendants of Clan Cosgrove of the Deisi Muman (Various Counties in Munster Province), Clan Cosgrove of Fermoy (County Cork), and the McOsker-Cosgrove Clan of the Mag Uidhir from County Fermanagh.

In addition to promoting Y-DNA testing among Cosgrove males, we also welcome genealogists who have conducted autosomal DNA testing to join our project as well, as long as they either carry the Cosgrove surname as their last names or have Cosgrove family lines in their trees.   New DNA project members can buy a Family Finder autosomal DNA test direct from the Family Tree DNA website or they can transfer a copy of an existing test from one of FTDNA's competitors such as MyHeritage, Ancestry.com, and 23andMe.  

It is strongly recommended that people wait for sales before purchasing a DNA test.  Family Tree DNA often has several sales throughout the year, though it is hard to predict which tests and upgrades will be placed on sale.  Typically, all tests and upgrades are on sale during the annual holiday period in Nov and Dec.  Sales normally occur in late April in conjunction with National DNA Day (normally around 25 April), Mother's Day in May, and Father's Day in June.  We usually witness a sale in August.  Short sales may pop up without prior notice (such as in conjunction with the annual RootsTech Genealogy Conference in Feb/Mar)).   Sales periods offer the best prices compared to other prices obtained through other discounted programs.   

While waiting for the next sales period, new members can join the Facebook group while they wait to join the DNA project (see the link below).

Cosgrove Surname Project at Family Tree DNA:  https://www.familytreedna.com/groups/cosgrove-surname-project/about/background

McOsker-McCusker DNA Project at Family Tree DNA: https://www.familytreedna.com/groups/mcosker/about 

(Family Tree DNA requires a person to purchase a DNA test from its site or transfer a copy of an autosomal DNA test, such as the AncestryDNA or 23andMe test results, to its site to become a member.  Once you join, you are a member for life with no subscription fees (at least for the foreseeable future).

Cosgrove Surname Project Facebook Group: https://www.facebook.com/groups/921428441309363/

Blog for the Cosgrove One-Name Study: https://cosgrove.one-name.net