Reilly Family DNA

Reilly is the 11th most common surname in Ireland. If you work on your family tree long enough, you’re bound to find a connection to the name.

For myself, I found the link when I learned the maiden name of one of my 5th-great grandmothers (yes, that’s 5 greats): Ann Reilly. She was born in about 1803 in Lurgan Parish, Co. Cavan, and immigrated to Canada.

Surname Overview & Geography

The Reilly surname is dominant in Co. Cavan & Co. Meath, where it is well documented for centuries. The name derives from O’Raghaillaigh, which means “descendant of Raghallach.”

Surname variations include: Reilly, Rielly, Riley, O’Reilly, O’Reiley, O’Rielly.

Here’s a map of Reilly births between 1864-1890. This shows the top 15 Irish registration districts for Reilly births. The darker the green, the more births. Cavan had the most (2,409), followed by Dublin (2,390) & then Granard (1,960), which neighbors Cavan.

Target Ancestor

I got really lucky because my Ann Reilly came from a parish that has early Catholic church records (back to the 1700s), and rare 1821 census returns that have survived. And that parish of origin was noted in Canadian records.

Her parish of Lurgan would fall in the Oldcastle registration district – one of the districts green in the map above – just east of Granard, and southeast of Cavan.

Thanks to the 1821 census, I learned that Ann’s parents were Phillip & Judith Reilly.

1821 Census, Bruse, Parish of Lurgan, Co. Cavan

Philip Rielly[sic], age 56, farmer
Judith, his wife, age 52, spinster
Patrick, his son, age 12
Stephen, his son, age 13
Philip, same, age 8
Thomas, same, 16, labourer
Edward, same, 20, labourer
Anne, daughter, 17, spinner
Lucy, daughter, 5
Mary, same, 7
Anne, his niece, 15, spinner

(Note: A few doors down is a Francis Rielly, age 60, possibly a brother of Phillip, with wife, Mary, 47, daughter Anne, 10, and son Edward, 8.)

How did I determine this was my Ann? The age fits (17 years old), as does the location (Bruse, Lurgan Parish), but the real clincher was her brothers Stephen & Edward Reilly. The Catholic parish records show Stephen & Edward were godfathers to her children, and she was a godmother of their children.

Due to a gap in the Lurgan Parish records, a baptism record for Ann did not survive, but I did find her marriage to Owen Fitzsimmons, dated 28 Nov. 1823:

Owen is listed as Eugenius, the Latin form of his name. The townland of Bruise (sic) is in the margin. The witnesses were Patrick Reilly & Maria Fitzsimmons.

I found 7 children for Ann & Owen in the Lurgan Parish records:

  • Ann Fitzsimmons, Sept. 1824 [my ancestor]
  • Bernard Fitzsimmons, Jan. 1827
  • Mary Fitzsimmons, Apr. 1829
  • Julia Fitzsimmons, Oct. 1831
  • Catherine Fitzsimmons, June 1834
  • Edward Fitzsimmons, Dec. 1836
  • Eugene Fitzsimmons, Mar. 1842

The family immigrated to Cobourg, Ontario, Canada shortly after the birth of the younger Eugene. Bernard is “Bryan” in Canadian records. Ann Fitzsimmons married Thomas Bulger & she is my direct ancestor; Mary married Martin Wallace & moved to Wisconsin, USA; Julia married John Cauley; and Catherine died as a teenager in 1852.

Ann Reilly died in 1869 in Cobourg. Here is her death notice from the local newspaper:

“Deaths. In Cobourg, on Sunday morning last, after a lingering illness, Ann Reilly, wife of Mr. Owen FITZSIMMONS, Sen., a native of the parish of Lurgan, county Cavan, Ireland, aged 76 years. Requiescat in pace.”

It is worth noting that the death notice exaggerates her age a bit, but this was not uncommon back then based on my prior research & experience. The rest of the records together place her birth year as closer to 1803.

Known Kin

A number of Reillys of Lurgan Parish have been linked to my Ann Reilly through traditional records – early church records & the rare census extracts from her parish.

This includes a brother Stephen Reilly who married Mary Cahil in 1834 in the Parish of Bailieborough and had 7 children in Bruse, Lurgan Parish: Bridget, Catherine & Judith (twins), Ann, Patrick, Mary & Phillip Reilly.

A burial record was found for Ann’s father Phillip Reilly in Lurgan Parish, dated Feb. 1824. A baptism record was also found for Phillip in the earliest records for the parish. He was born in April 1765 to Hugh Reilly & Mary Farrelly. This birth year (1765) matches up with his age on the 1821 census. He had 3 sisters: Catherine, Ann & Bridget; and a brother Hugh Reilly. The younger Hugh is found in Cleggan townland, Lurgan Parish in the 1821 census, and he witnessed the marriage of his nephew Stephen Reilly in 1834.


To date, no direct male descendant of this Reilly family has taken a Y-DNA test. If anyone can confirm their lineage back to this Reilly family of Lurgan Parish & would like to take a Y-DNA test (or has already taken such a test), I would be very interested to collaborate with you.

Close Relatives per Autosomal DNA

With a family as large as this one – the Reillys were a very big family, I could just tell from the census & church records that have survived – I expected to find a few DNA connections.

I did not expect to find a 110-cM single segment shared between my great-uncle & one of these distant relatives.

This is a very large segment for an autosomal DNA link; usually only siblings, aunts/uncles & grandparents – close relationships – share a single segment as large as this. Granted, this distant relative only shared this single segment with my immediate family & no other segments. Something like this happens by chance; it is rare but it does happen.

I do wonder if it might indicate some endogamy or intermarrying. Perhaps Owen Fitzsimmons was related to Ann Reilly, for example. If he had some Reilly DNA as well, it would virtually guarantee Reilly segments to pass down, creating a higher likelihood for such a segment to survive today. Just one theory, and it could also just be a coincidence.

Regardless, I was able to confirm this segment is Reilly DNA through triangulation and phasing. Several smaller parts of this larger segment are shared by multiple distant Reilly cousins, and triangulation & phasing confirmed the DNA was consistent with the Reilly side for both our family & these matches. Not only that, but the DNA matches strongly indicated a Co. Cavan connection, and Ann Reilly & Owen Fitzsimmons are my only immigrant ancestors from Co. Cavan, so it must be through them.

This largest match descends of a Phillip Reilly, born in June 1850 in Lurgan Parish to Patrick Reilly & Margaret ‘Peggy’ Fitzsimmons. Patrick & Margaret married on the 13th of July 1840 in Lurgan Parish. They also had sons named Patrick & Thomas Reilly. Based on the shared matches & others who inherited this segment, I determined it’s a Reilly link, not Fitzsimmons. Patrick Reilly “fits” as the Patrick Reilly, born in 1809, son of Phillip & Judith Reilly of Bruse, Lurgan Parish, per the 1821 census – the brother of my Ann Reilly Fitzsimmons. It is interesting that the siblings both married Fitzsimmons & there may be something to that, but to date I have been unable to connect Margaret to my Owen. It’s also worth noting that Patrick Reilly witnessed the marriage of my Ann Reilly to Owen Fitzsimmons, as stated earlier.

Phillip Reilly, born in 1850, married twice: (1) Margaret Lynch, (2) Rose Mahan, and he immigrated to Illinois. The match who shares a large segment with my family descends of Phillip Reilly & Margaret Lynch. My family has other DNA matches who descend of Phillip Reilly & Rose Mahan.

Marriage of Phillip Reilly and Margaret Lynch. Phillip is identified as from Bruse.

Next, we match descendants of a Thomas Reilly & Bridget Curran. Thomas Reilly was born in about 1805 & again he “fits” with traditional records that show my Ann having a brother named Thomas, son of Phillip & Judith Reilly. He had a son Thomas Reilly in 1830 in Lurgan Parish who married a Rose Brady, and they had a daughter Bridget Reilly, born in March 1863 in Lurgan Parish. We descend of multiple of Bridget’s descendants. She married George Pickard and died in Illinois.

There is a Thomas Reilly, son of Phillip Reilly and Judith Rodden, of Killann Parish, Co Cavan, who married a Margaret Toole on Jan. 25, 1850 in Toronto, Ontario. It’s worth noting Killann Parish is less than 5km from Lurgan. This may or may not be the same elder Thomas, but it’s worth noting the geographic proximity & the same names. That could indicate a maiden name for our Judith.

As time goes on, more DNA evidence may arise to help paint a better picture on our Reilly family. Please leave a comment below or contact me if you may have info on the above families, or if you’d like to share your own Reilly / O’Reilly connections.

Looking for the latest Irish family history news and genetic genealogy tips? Sign up for our newsletter:

Success! You're on the list.

Want to show off your Irish pride? Have a look at these:

(The above links are affiliate links, which means we may receive a small commission from your purchase at no extra cost to you. Thank you for supporting Irish DNA Net!)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s