Welcome to the Scrapbook pages for the McCarthy Surname Study, which analyses the Y-DNA of men named McCarthy or a spelling variant or agnomen associated with this name. The files made available below support the main Study website at: https://www.familytreedna.com/groups/mccarthy-surname-study/about

Our McCarthy Surname Study books

We have published (via Amazon) Kindle and paperback versions of two books entitled Tracing Your McCarthy Family Tree.

Book 1 is for complete beginners but takes research up to and including the ordering a Y-DNA test. It includes a chapter on tracing your ancient ancestry.

Book 2, which is subtitled Using Y-DNA, explains the essential nuts and bolts of Y-DNA testing and many of the techniques we use in analysing and presenting our members’ data. There are also chapters on the development of the Study and recalling our 2013 and 2017 ‘Gatherings’.

All proceeds will be reinvested in the McCarthy Surname Study (and, where appropriate, the R Z16526 and Subclades Project) funds for the furtherance of the study of M(a)cCarthy ancestry. To minimise printing costs and maximise royalties the paperback versions have been published in black and white. However this colour version of the double helix diagram on page 2 of Book 2 will better enable readers to follow the narrative.

Tracing Your McCarthy Family Tree Book 1.
Tracing Your McCarthy Family Tree: Book 1.

The books may be purchased in local currency from Amazon publishing sites in USA, U.K., Canada, Australia, France, Brazil etc.. Book 1 is available here if purchasing in USA and here if purchasing from Amazon U.K, while Book 2 can be found here and here respectively.

Our Posters

If you are considering testing please click on either of these posters.

here if you reside in Britain and Ireland

here for anywhere else in the world

Y-DNA Phylogenetic Trees

These trees show the genetic relationship between McCarthys in various branches of the overall Y (male)-tree of mankind illustrated in Fig. 1 below. The designations R-L21 Group A, B, C etc. are specific to the McCarthy Study and have no significance beyond this. Non-McCarthy Y-DNA testers are identified where their presence on trees may give clues as to McCarthy members’ origins or, in R-L21 Group B only, their own paternal ancestry lies in the eponymous Cárthach and / or the early McCarthy dynasties. The R-L21 Group B tree is a subset of that belonging to the R-Z16526 and Subclades Project, the whole of which is also provided here for convenience. This Z16526 tree thus traces the paternal ancestry of Cárthach.

Haplogroup E1b1b1
SNP EM35.1 (E1b1b1)2022 Feb 27
Haplogroup I1
SNP I-M253 (I1)2022 Jun 09
Haplogroup I2a1
SNP I-L470 (I2a1)2022 Nov 11
Haplogroup of R-U106
SNP R-U1062022 Jun 11
Haplogroup of R-U152
SNP R-U1522022 Jun 07
R-L21 Group A and Irish Type II (also on behalf of the R1b-CTS4466 Plus Project)SNP R-S1115 (Irish Type II)2022 Dec 01
Age Guide for R-L21 Group A and Irish Type II treeIrish Type II Tree Mutation Block Age Table 2022 Dec 01
R-L21 Group ATemporarily withdrawn. Please use the above Irish Type II tree.2022 Apr 20
Haplogroup of R-Z16526 (on behalf of the R Z16526 and Subclades Project)SNP R-Z16526 (leading to ZS4606)2022 Jun 29
R-L21 Group B (continuing from Sheet 3 of the R-Z16526 tree)SNP R-ZS46062022 Aug 21
Age Guide for R-Z16526 tree (including McCarthy R-L21 Group B subset)R-Z16526 Tree Mutation Block Age Table2022 Jun 26
R-L21 Group CSNP R-M222 (Irish Type I)2021 Nov 19
R-L21 Group DSNP R-L5132021 Mar 05
R-L21 Group ESNP R-Z2552022 Nov 07
R-L21 Group FSNP R-Z253 (including Irish Type III)2022 Oct 11
R-L21 Group GSNP R-CTS33862020 Dec 28
R-L21 Groups H, I, J and NSNPs R-FGC35995, R-Z251, R-S1051 and R-FGC100462020 Oct 16
R-L21 Groups K, L and PSNPs R-DF5, R-3000 and R-Z162942022 Jun 14

Project Charts and Diagrams

Figure 1From Africa to McCarthy2020 Dec 30
Figure 2Development of principal McCarthy Septs2022 Aug 19
Figure 3Breakdown of McCarthys by haplogroup2022 Feb 25
Figure 4McCarthy Ancestral Haplotypes2022 Aug 05
Figure 4aY-DNA111 Mutation Frequencies2021 Jan 02
Figure 5McCarthy Sept names and Agnomina in use in the past few centuries2020 Sep 28

Pedigree Library

This is the new home for our members’ pedigrees, formally located on our WorldFamilies site (which was closed down by the site operators in May 2018).

McCarthy Surname Study Pedigree Library 2018 Aug 13


Some book and manuscript references relating to McCarthy ancestry. Many are freely available to download.

Reading list 2021 Jun 05

Scholarly Articles, Presentations etc.

The Rise of Meic Carthaig and the
Political Geography of Desmumu.

by Paul MacCotter
Journal of the Cork Historical and Archaeological Society, 20062006
The McCarthy family tree by R.C.McCarthyThe story of the MacCarthys of Ardcanaght.2012
MacCarthy Gathering PostersPosters for the MacCarthy Gathering to celebrate The Homecoming
of the Daniel MacCarthy Glas Archive
, Dunmanway,
Co. Cork, 26-28 May 2017.
2017 May 31
The Genetic Identification of McCarthysSlide show for Tribe101 presentation2022 Oct 04
Charles Mac Carthy in the Archives of Bilbao
by Oisín Breatnach
Sources in the Archives of Bilbao giving a 17th/18th
family history spanning four generations,
with suspected MacCarthy Reagh origins (study ongoing).
2017 Jul
Freke Estate (Cork) Survey of 1787/88
curated by Pádraig Mac Cárthaigh
Link to Pádraig’s curation of the survey of the estate of Sir John Freke of
Castle Freke, near Rosscarbery, Co Cork by the noted 18th-century Dublin land surveyor Thomas Sherrard.
2019 Jun 05
Dunmanway Castle originally created
by Fintan Mac Carthy
Link to Wikipedia article on one of two castles which were homes to the MacCarthy Norsa (an Fhorsa) family.2020 Jul
Daniel Mac Carthy Glas originally created
by Fintan Mac Carthy
Link to Wikipedia article on Daniel Mac Carthy Glas.2020 Aug
Phylogenetic alignments with
genealogies of descent from Ailill Ólom

by N.D.McCarthy
A comparison of Irish Type II (McCarthy R-L21 Group A) phylogeny with ancient genealogical texts pertaining to first millennium ancestries.2021 Apr 14
Age guide dates for phylogenetic trees by N.D.McCarthyInformation concerning Mutation Block Age Tables provided in the Y-DNA Phylogenetic Trees section.2022 Jun 25