Oneil
Masculine · “Irish Niall”
Oneil is overwhelmingly a boys’ name — 1,757 boys against 17 girls since 1880.
Two to three million men in north-west Ireland and its diaspora carry a Y-chromosome signature that traces to a single man living around the fifth century. Geneticists have connected it, cautiously, to the dynasty that produced the O'Neills.
How old is the name Oneil?
Oneil first appears in US birth records in 1892 — 133 years ago. The typical Oneil alive today was born around 1960, making them about 65 years old. About 1,100 people named Oneil are estimated to be alive in the US today.
When was the name Oneil most popular?
Oneil peaked in 1892, reaching #1066 nationally. Today it ranks #9714, 8,648 places below that high. See the whole 1892 chart.
Lists built from the same records:
Where it comes from
From Niall to Oneil
The story of Oneil
A study published in 2006 identified a Y-chromosome haplotype carried by around one in five men in north-western Ireland and by a substantial number in Scotland and the diaspora, and estimated a common ancestor in roughly the fifth or sixth century. The researchers noted its concentration in the historical territory of the Ui Neill and among men with surnames traditionally associated with that dynasty, and suggested Niall of the Nine Hostages as a candidate. Later work has been more cautious: the dating is wide, the identification with any named individual is unprovable, and the pattern could reflect a lineage rather than a person. What is not in doubt is that some male line in early medieval Ireland left an extraordinary genetic footprint, which is what a dynasty with power over reproduction looks like a thousand years later.
Meaningscholars disagree
Irish Niall, of disputed meaning
Oneil is a spelling of O'Neill, Irish O Neill, descendant of Niall. The personal name Niall is of disputed meaning; champion and cloud have both been proposed and neither is established. The family claimed descent from Niall Noigiallach, Niall of the Nine Hostages, a fifth-century high king. The American peak is 1892.
How the name formed
- Niall
- O Neill
- Oneil
Related forms: O Neill · O'Neill · MacNeil
Pronouncing Oneil
oh-NEEL
Two syllables, stress on the second. The apostrophe of the standard surname spelling is dropped here; the O is the Irish word for descendant.
Nicknames for Oneil
Moderate
What the data says
146 years of official birth records
The long climb, and where it stands now
The same years in position rather than babies
- First recorded
- 1892
- Most boys named
- 192438 — the highest on record
- Peak rank
- #1066reached in 1892
- Change vs 2023
- −12.5%7 in 2025, from 8
Rank is a position, a count is a headcount, and they move independently — a name can hold its rank while the number of babies behind it falls. Source: U.S. Social Security Administration.
Oneil in other languages
The same name elsewhere
- O Neill in Irish — same name
- O'Neill in English — spelling variant
- MacNeil in Scottish — related form
Oneils among us
people named Oneil are estimated to be alive in the US today
About 1 boy in 244,011 born in 2025 was named Oneil
Estimated from SSA birth records and published actuarial life tables. Method
Is it right for you
What happens to a name after it peaks
Fashion outlook
Oneil sits in the calm middle of the cycle — neither chasing a wave nor sliding off one. Middle-of-the-cycle names age slowly and predictably.
A scored estimate from 146 years of naming cycles — not a prophecy. Great names outlive statistics. How this is scored
Oneil beside its neighbors
The names ranked closest to Oneil in 2025, in babies rather than position — the bars are to scale.
US boys given each name in 2025.
The trade-off
- Neil is available as a short form and is a complete name.
- The stressed ending gives it a firm final beat.
- It is a genuine Irish surname with a documented dynasty behind it.
- O'Neill with an apostrophe is the standard surname form.
- It reads clearly as a surname.
- The meaning of Niall is genuinely disputed.
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Oneil
Masculine · #9714 in the U.S.
Frequently asked
- How many Oneils are there in the world?
- No country counts the world's names, so there is no worldwide figure — anyone quoting one is estimating. About 1,100 people named Oneil are estimated to be alive in the US today.
- How popular is the name Oneil in 2025?
- Oneil ranks #9714 among US boy names in 2025, with 7 babies given the name.
- How rare is the name Oneil?
- About 1 in every 244,011 US boys born in 2025 was named Oneil — 7 in all.
- Will my child share the name Oneil with classmates?
- Oneil will almost certainly be the only one in school.
Ranked beside Oneil
Names sitting at a similar level of popularity right now.
Vern#9714 · Abrahm#9714 · Sid#9714 · Hartwell#9714 · Kwan#9714 · Adrean#9714 · Chancey#9714 · Bob#9714
Looking for what else is popular rather than what resembles Oneil? See the current top 100.
Choosing between Oneil and another name?
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US figures from the Social Security Administration. 1880–2025. Data & methodology
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