McCool Name Study

Privacy Level: Open (White)
Date: [unknown] [unknown]
Location: [unknown]
Surnames/tags: McCool McCoole McCull
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Please understand that the McCool Name Study is under active development in mid 2023. Many parts are incomplete or are changing quickly. Thanks for your understanding; suggestions for further improvement are always VERY welcome.


About the McCool/McCoole One Name Study

In this one-name study, McCool researchers work together to determine how people with McCool and McCoole surname ancestors are (and are not) related to each other. We know (from a limited number of Y-DNA tests) that there are at least six distinct, unrelated (on their direct paternal line) groups of McCools in the world. We will probably discover 2 to 4 additional McCool lines in the future.

How to Participate

Please contact the study's coordinator, Kevin Ireland, or post a comment at the bottom of the page. Describe your own McCool research goals; we welcome any level of participation. Add our sticker to your McCool profiles by including the following text as the first line after Biography! {{One Name Study| name = McCool| category = McCool_Name_Study}}

This profile is part of the McCool Name Study.

If you're a McCool descendant (or descendant spouse), regardless of your current surname, we invite you to join our large, private McCool History Facebook group. As of June 2023, we have over 940 members. Request to join the group at - and be sure to answer the membership questions.

Study Goals

We have several study goals as of June 2023, but will adjust and add to them based on participant feedback.

  • Use an increasing number of Y-DNA tests to identify all/most of the distinct McCool lines in the world. Ideally, we'd love to have one Y-DNA test from a male McCool-surname descendant of the McCool second-great-grandfather of the oldest living McCool-line person in your family. In other words, we'd love to have one Y-DNA test among every group of older McCool third-cousins.
  • Build a database of AncestryDNA-tested McCool descendants - and encourage more McCools to test. We aren't collecting anyone's DNA test results, but we want to know how tested McCools fit into our McCool WikiTree lines.
  • Build up and clean up McCool information on WikiTree. Please focus your time on your ancestors, as other McCools can't see information about living people.

McCool History Blog

Discussion of a wide-range of McCool / McCoole topics. Feel free to chime in, but please don't remove other people's posts.

Lists of McCools with common given names

The common McCool practice of naming sons after their grandfather means we end up with a LOT of McCool men who share the same name and were born in the same place at relatively similar times. We'll attempt to differentiate here among lists of men with identical or similar names.

Early McCool Census Records by Place

We will gather Census records of the earliest McCool settlers in various areas and try to identify relationships between them.

McCool Places

Examining clusters of McCools in different geographic areas can help us identify likely common lines.

Australia and New Zealand

Multiple unrelated lines of McCools have emigrated to Australia and New Zealand.

McCool Name Study - Canada

Multiple unrelated lines of McCools have emigrated to Canada - many before there was a country named Canada.

England and Wales

We know little about the roots of McCools whose ancestors lived in England (and Wales, if any).

Ireland (non-Ulster)

Very few McCools lived in Ireland outside of Ulster until modern times.

Ireland - Ulster

Most McCools and McCooles in the world have ancestors who lived in Ulster. The highest densities were from County Donegal and County Londonderry, but with a significant number from County Tyrone and County Antrim. These counties are extremely close geographically; migration between them was common.


Most McCool lines are believed to have Scottish roots. Some County Donegal lines in Ulster may have more non-Ulster Irish roots. Of course, most Scots arrived in ancient times via England or Ireland. McCool lines aren't currently believed to have Viking roots.

McCool Name Study - United States (and early colonial areas)

McCool descendants live in every state today, but there have been important historical clusters from different lines. Dive in here to help connect your ancestors accurately.

McCool Y-DNA Testing

McCool Y-DNA Campaign

This research area explains the importance of McCool Y-DNA tests - and how family members can contribute small amounts (directly to the testing vendor) to support more Y-DNA tests in their line.

McCool Y-DNA Results

This section lays out a summary of the current McCool Y-DNA tests.

McCool Y-DNA Lines

In this study, we'll define a confirmed McCool line as all descendants of the earliest-known related individual named McCool (and spelling variations), regardless of their current surname. We will use results from Y-DNA and AncestryDNA testing to try to identify and separate unrelated (on the direct paternal line) McCool lines.

As of August 2022, we have identified the following distinct McCool lines (lines and descriptions under construction). Note that a "true" distinct line would need to have at least two matching tests from distant cousins:

Possible Toberhead Lines

As of October 2022, we have two sets of different Y-DNA-verified McCool lines whose paper trails show a line of descent from John McCoole Sr. By definition, these two lines can't share a common paternal line ancestor, so at least one of the paper trails has an error.

R1b MC01 - pos Toberhead McCool Line

The patriarch of the Toberhead line was John McCoole, who established the Hillmount Farm in Toberhead Townland, County Londonderry, Ireland [now Northern Ireland] about 1680. We were originally confident that we knew which lines descend from John, but we now have two competing, unrelated McCool paternal lines that could be his descendants. Until we get Y-DNA tests from descendants of some of John's younger sons (especially James and Walter), we won't know which is the Toberhead line.

We have seven matching tests (including two Big Y-700 tests) in one group - and two matching Big Y-700 tests in the other group. Both groups are from old McCool lines established no later than about 1700; there's nothing recent about either of them.

Until we get more Big Y-700 tests, we will designate the larger group as the McCool - McPherson group (because the McCools match to so many McPherson/MacPherson men). The second group will be referred to as the McCool - MacMillan group. Each group descends from separate common ancestors whose descendants came to be named either McCool or McPherson (and other surnames) - or McCool or MacMillan (plus others).

R1b MC02 - pos Toberhead McCool Line

The R1b MCC02 line is the McCool - MacMillan group. It includes all descendants of Archibald McCool (abt.1740-1780), who died (along with his eldest son) at the Battle of Charleston fighting on the side of the British. His remaining children and his widow moved from Orange Co NC to Townsend Ontario about 1794. It also includes descendants of James Adam Gettis McCool (1821-1900).

This line may be part of the Toberhead McCool Line, but our two Y-DNA tests are insufficient to determine that. We need more McCool Y-DNA tests from the descendants of the younger sons of John McCoole Sr.

Venango Co PA Line

A large number of McCool descendants have lived in Venango Co PA since about 1800. All or most are believed to descend from George Plummer McCool Sr (abt.1765-abt.1815). AncestryDNA testing suggests that they most/all are related to each other (although matches could be on different lines). We have three matching Y-DNA tests on this line that may also link it to County Londonderry, but it is definitely NOT related to the Toberhead McCool line.

Centre Co PA Line

This line (or lines) includes Centre, Mifflin, and Huntingdon Co PA McCools. It includes all descendants of Michael McCool (c1773 Ireland or Chester Co PA to c1842 Centre Co PA). We have no Y-DNA tests yet on this line. It's possible that they're related to the Toberhead McCool line, but we have no supporting evidence of that yet.

There is a second Huntingdon Co PA line that descends from George McCool (1824 Co Londonderry to 1910 Huntingdon Co PA) that arrived from Ireland c1847. We have a Y-67 test from this line, but don't yet know if descendants are related to the Centre Co PA line.

County Donegal Lines

It's likely that multiple McCool lines have passed through County Donegal. We have one Big Y-700 test that is believed to have a County Donegal connection; it doesn't yet match to any other McCools tested. We have one known Y-67 test from this line that doesn't yet match any other McCools tested. It's distantly related (probably pre-surname timeframe) to a FitzPatrick line.

We don't yet know if either of these tests are related to the large Michael McCool line that includes many emigrants to northern Ontario and western Canada. We need more Y-DNA tests.

Tyrone County Ireland Line

We have one Y-DNA test from this line that doesn't match anyone else yet. Lots of questions here.

Also see the related surnames and surname variants.

Wiki Profile Notes

Early McCool research is very difficult due to incomplete records and many identical names. Our understanding of familial relationships has sometimes evolved as new information is discovered - but may not have been communicated to everyone. As a result of these factors, researchers sometimes disagree on exact lines of descent or spouse maiden names. This page is used to discuss various theories with profile managers before making changes to parent, child, or spouse connections on WikiTree.

Other Research Areas

McCool Brick Walls

Please add a link to the WikiTree profile of any McCool whose parents are unknown or uncertain.

McCool Wills and Bible Entries

Please add a link to the WikiTree profile of any McCool who left a will to the McCool Wills page. Similarly, add a link to McCool (and descendant) profiles with dates recorded in a family bible.

McCool Quakers

There are almost 1,000 known Quaker records about people named McCool or McCoole - and perhaps many more. The Toberhead McCool line became active Quakers in the mid/late 1600s; most McCool Quakers are believed to descend from this line.

Membership (feel free to add your name and area of interest here)

  • Kevin Ireland Study coordinator. Also the McCool specialist in the COLE surname project at FTDNA (for Y-DNA testing). DNA-confirmed member of the Townsend Ontario McCool line.

Membership Sticker

... ... ... is a member of the McCool Name Study Project.

Once you are ready to go, you can also show your project affiliation with the ONS Member Sticker. Add the adjoining "member" text to the top of your personal WikiTree profile.


Related Surnames and Surname Variants

External Resources

McCool History Facebook Group: all McCool descendants and spouses (regardless of current surname) are welcome to join our large, private FB group at

New McCool Surname Project at FamilyTreeDNA: - although McCool has been tracked in the COLE project for years, we're starting a new surname focused only on McCool, McCoole, and close spelling variants. All McCool men who take a Y-DNA test should join both projects (at least for now).

Cole Surname Project at FamilyTreeDNA: - although no McCool lines match on Y-DNA to any Cole lines, the families are grouped together in a single project at FTDNA. All McCool men who take a Y-DNA test should join this project.

Archived McCool Forum Posts: has archived several hundred posts about the McCool surname. Much of this information is older may not reflect more recent findings - but some is probably useful.

Future Project Pages

The following content is in the earliest stages of development; these are definitely NOT ready for release yet.

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  • Private Messages: Contact the Profile Managers privately: Kevin Ireland and One Name Studies WikiTree. (Best when privacy is an issue.)
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Comments: 3

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I am researching Coulsons from Ireland; as McCool is a variation if Coulson (and Mac Cumhaill) I wonder if you would interested in including these surname variants.
posted by Lynne Colson
Hi Lynne, my suggestion is to request that a separate one-name study be started for the Coulson/Colson surnames (you can have up to three surnames on a study, but pick the one you want to be used in the study name). There are about 1,000 Colsons and almost 1,500 Coulsons on WikiTree which is certainly enough to support a study of its own. WikiTree will start one for you even if you don't qualify as the project administrator yet. You can effectively act as the admin until you get enough contributions to qualify (or recruit someone to take on the job.

I don't see any Y-DNA matches between those families and McCool lines, so I'd rather not merge them in here. The names are similar, but don't seem to share common ancestors.

For more info, visit or

posted by Kevin Ireland
edited by Kevin Ireland
Greetings, everyone. I'm excited to get this McCool one-name study set up in October 2020. I'll be working on the project description first. Please comment if you're interested in participating in the project.
posted by Kevin Ireland