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About us

While a surname itself may give us incomplete or misleading or, at best, only general information about the origin of a family, DNA-testing can give us concrete evidence for identifying and separating family lines.  Y-chromosome DNA testing is especially helpful because the male Y-chromosome is handed down, father to son, unchanged through the generations, except for rare mutations which, in themselves, can be helpful indicators of branching. The accessibility and affordability of family DNA testing is doubtless the greatest technical advance in the history of genealogical research because -- at long, long last -- we have a tool to break down those brick walls!

Who Can Join the Carroll Project? Anyone with a Carroll surname, or a variant thereof, is invited to join. Anyone from another surname project who matches a Carroll DNA category also is invited.

Where Can I get Help? The Carroll DNA project was started by Kevin Carroll in September 2004. Peter Biggins has been filling in as administrator since August 2012. Send Peter an email if you have any questions about initial Y-DNA testing or upgrading after viewing this page.

How Do I Get Started? Assuming you are entirely new to FTDNA, you should start by ordering from the Carroll DNA project either the Y-DNA67 or Y-DNA111. The lesser tests are generally not nearly as helpful. To order, click on Join Request at the top of this page. You pay with a credit card. FTDNA will give you a password-protected homepage. Then they send you a kit that you use to swab the inside of your cheek twice. You send the kit back to them and they take a couple months to test your DNA. In the meantime, you add information about your most distant Carroll ancestor: name, birth place, birth year. They will post your results on your homepage and the Carroll project Results page. We will move your results to an appropriate DNA category. Your homepage will have a list of the names of people you match up with and their email address.  The people you match up with will see you in their matches. The match information will expand as more people test with FTDNA. After your results have been posted, we will be able to tell what SNPs you should test. SNP results may indicate a different category. Listed below are suggestions as to additional projects you might join, depending on your DNA category.

What Are SNP Categories? One of the things we have learned from Y-DNA testing is that practically all surnames have multiple unrelated origins. And the name Carroll is no exception.

Multiple origins can be identified with SNPs (single nucleotide polymorphisms), unique markers, and DNA modals. The results table for this project contains over 25 categories that differentiate Carroll participants by origin.

The largest SNP category is DF21 Clan Colla, which includes about 15% of Carrolls. The next largest SNP categories are M222 Northwest Irish, DF21 Ely Carroll, and L21, each with about 10% of Carrolls.

Is there any ancient history associated with the SNP categories? Woulfe's 1923 Irish Names and Surnames says the name Carroll has many different origins and identifies six different origins of Carrolls:

Ó CEARBHAILL—IO Carrowill, O Carwell, O Carvill, O'Carroll, Carroll, Carvill; 'descendant of Cearbhall' (a very common Irish personal name). There are several distinct families so named, of which the following are the best known:

(1) Ó Cearbhaill of Eile, who derive their name and descent from Cearbhall, lord of Eile, who fought at Clontarf. The head of this family was originally lord of all Eile, which comprised the baronies of Clonlisk and Ballybritt, in the present Offaly, and Ikerrin and Eliogarty, in Co. Tipperary; but after the Anglo-Norman invasion, Ikerrin and Eliogarty became tributary to the Earl of Ormond, and only the portion of Eile subsequently called Ely O'Carroll, remained in possession of O'Carroll, who resided at Birr. This family is now very numerous. [See R-L21, DF21, 492=11, Ely Carroll modal category.]

(2) Ó Cearbhaill, of Oriel. This family is of the same stock as the MacMahons and Maguires, and were chiefs of Oriel until about the period of the Anglo-Norman invasion, when they disappear from history. They are still numerous in Monaghan and Louth. [See R-L21, DF21, 511=9, 425=0, 505=9, Clan Colla modal category.]

(3) Ó Cearbhaill of Loch Lein, anciently chiefs of the Eoghanacht of Loch Lein, the district about Killarney, until dispossessed by the O'Donoghues. [See R-L21, CTS4466, Irish Type II/South Irish modal category.]

(4) Ó Cearbhaill of Ossory who are descended from Cearbhall, a celebrated chieftain of Ossory at the middle of the 9th century. [See R-P312, DF27, 390=25, 481=24, 520=21, Dwyer/Ryan modal category.]

(5) Ó Cearbhaill, of Tara, a branch of the southern Ui Neill. This family disappeared from history at an early period. [See R-L21, DF23, M222, Northwest Irish/Niall of the Nine Hostages category.]

(6) Ó Cearbhaill of Calry, in Sligo and Leitrim. The MacBradys of Cavan are said, but erroneously, to be a branch of this family.

What Are the Chances of Being Related to Charles Carroll of Carrollton? Many American Carrolls think they are related to Charles Carroll of Carrollton, signer of the Declaration of Independence. Charles Carroll of Carrollton was descended from the Ely Carrolls, and a descendant of his is included in the DF21 Ely Carroll category. The probability of being related to Charles Carroll of Carrollton is about 10%. Fortunately, there are many other fine Carroll categories for the other 90% of Carrolls.

Why Should I Test for a SNP? If you test positive for a  SNP, it will mean that you have a group that your DNA belongs to that is smaller than the group that you belong to now. You can look at the names and places of the other people in the new smaller group and perhaps draw some conclusions about your ancestors. Someone will probably be able to estimate when the new group was first created, which would be a date later than your old group. And it might be possible to tie the group in to a ancient pedigree. You will not have to concern yourself about other new groups that are parallel to your new group. If you test negative, you are back to square one, but at least you will have learned that you do not belong to that newer group. Perhaps another testing situation will present itelf in the future. In either event, you will have furthered the general research into the group's DNA.

What SNP Tests Should I Order? The best SNP test is Big Y-700. It will give you your actual SNP and 700 markers that predict SNPs. The most reliable estimates are made with tests for 67 or 111 markers.  

Participants are placed in SNP categories based on estimates in some instances. 

What SNP Project Should I Join? Participants in the Carroll project are assigned to categories based on projected or actual SNPs. You should consider joining projects devoted to your SNPs if you are not already a member. Administrators of these projects can suggest what SNPs you should test for to get to your terminal SNP if you are not already there. Following are the SNP categories, by haplogroup, with a suggestion as to which SNP project one should join.

Geographical Projects. Participants with Munster geographical origins should consider joining the Munster Irish project. Munster includes the Ireland counties of Clare, Cork, Kerry, Limerick, Tipperary, and Waterford.

Participants with Ulster geographical origins should consider joining the Ulster Heritage project, Ulster includes the Ireland counties of Cavan, Donegal, and Monaghan and the Northern Ireland counties of Antrim, Armagh, Down, Fermanagh, Londonderry, and Tyrone.