Brennan
Masculine · “descendant of Braonán”
Brennan is given to both — 33,258 boys and 2,229 girls since 1880. See Brennan as a girl nameSee other names given to both
Brennan began as an Irish surname, Ó Braonáin, borne by several quite unrelated families — in Kilkenny, in Westmeath, in Kerry, in Fermanagh — long before anyone thought to put it in front of a family name. In the mouth it is two easy beats with the weight on the first, and it has kept the same spelling on both sides of the Atlantic for generations.
How old is the name Brennan?
Brennan first appears in US birth records in 1916 — 109 years ago. The typical Brennan alive today was born around 2003, making them about 22 years old. About 32,500 people named Brennan are estimated to be alive in the US today.
When was the name Brennan most popular?
Brennan peaked in 2009, reaching #242 nationally. Today it ranks #1002, 760 places below that high. See the whole 2009 chart.
Brennan appears on these lists:
Works in Irish families too:
Where it comes from
From Braon to Brennan
The story of Brennan
Brennan is one of the most widespread Irish surnames, and unusually it does not come from a single family: distinct Ó Braonáin lines rose in Ossory, Westmeath, Kerry and the north, all reduced to the same English spelling when Irish names were written down by English-speaking clerks. Mac Branáin of Roscommon was flattened into Brennan too, which is why the name has more than one ancestry behind it. Irish emigration carried it to America in great numbers through the nineteenth century, where it lived for decades purely as a family name. Its move to the front — part of a long American habit of promoting Irish surnames to first names, alongside Ryan, Kelly and Casey — happened in the twentieth century and gathered pace late.
Meaningscholars disagree
descendant of Braonán, a name built on Irish braon
The surname is Ó Braonáin, 'descendant of Braonán'. Braonán is a diminutive of braon, which means 'drop, moisture' and is also used for 'tear, sorrow' — so the root is read both ways. Separately, the Roscommon surname Mac Branáin, from bran 'raven', was also anglicized as Brennan, so some Brennan families descend from that line instead.
How the name formed
- Braon
- Braonán
- Ó Braonáin
- Brennan
Related forms: Ó Braonáin · Mac Branáin · Brennen · Brennon
Pronouncing Brennan
BREN-un
Stress on the first syllable. The second is a light, unstressed -un or -in; both are heard and neither is wrong.
Nicknames for Brennan
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
- 1916
- Most boys named
- 20091,464 — the highest on record
- Peak rank
- #242reached in 2009
- Change vs 2023
- +6.1%226 in 2025, from 213
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.
Brennan in other languages
The same name elsewhere
- Ó Braonáin in Irish — related form
- Mac Branáin in Irish — related form
- Brennen in English — spelling variant
- Brennon in English — spelling variant
Strongest US states over the last decade: Texas, California, Louisiana.
Brennans among us
people named Brennan are estimated to be alive in the US today
About 1 boy in 7,558 born in 2025 was named Brennan
Estimated from SSA birth records and published actuarial life tables. Method
Is it right for you
What happens to a name after it peaks
The Darrel test
Every popular name lives one long story — a climb, a peak, a slow settling back. Brennan's later chapters haven't been written yet, so we borrowed them: Darrel climbed just as high around 1939, and its whole arc is on record. Line the two peaks up, and Darrel's path sketches the road Brennan is walking now.
Brennan 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
Where Brennan is headed
Brennan is easing off slowly — about 18% fewer babies a year by 2030 if the trend continues.
High confidence — fitted on official counts through 2025.
A damped-trend projection of the official birth data — a sketch of momentum, not a promise. Every name's forecast, ranked.
Brennan beside its neighbors
The names ranked closest to Brennan in 2025, in babies rather than position — the bars are to scale.
US boys given each name in 2025.
The trade-off
- One spelling has dominated for generations, and it is the one most people will guess from hearing the name.
- Two syllables, no silent letters, and phonetic for English speakers on first sight.
- A documented Irish surname with centuries of unbroken written record behind it, and several distinct family lines.
- Works as a surname as well as a first name, so it sits easily on a résumé or a jersey.
- Common enough to be recognized everywhere, uncommon enough that a classroom is unlikely to hold two.
- Brendan is the real hazard. The two names share a first syllable and an Irish origin, and Brennan will be called Brendan by teachers, receptionists and new colleagues fairly often.
- Brennen and Brennon both exist, so expect to spell it aloud now and then — though the standard form is the one people default to.
- Surname-first names read as slightly formal to some ears, and Brennan has no obvious softer or more playful alternative beyond Bren.
- It is stepping back from its high point, which means a Brennan born now will share the name mostly with people in their twenties rather than with classmates.
Nobody names a baby alone.
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What they receive
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Brennan
Masculine · #1002 in the U.S.
Frequently asked
- How many Brennans are there in the world?
- No country counts the world's names, so there is no worldwide figure — anyone quoting one is estimating. About 32,500 people named Brennan are estimated to be alive in the US today.
- How popular is the name Brennan in 2025?
- Brennan ranks #1002 among US boy names in 2025, with 226 babies given the name.
- How rare is the name Brennan?
- About 1 in every 7,558 US boys born in 2025 was named Brennan — 226 in all.
- Will my child share the name Brennan with classmates?
- Brennan will almost certainly be the only one in school.
Ranked beside Brennan
Names sitting at a similar level of popularity right now.
Benito#1002 · Howard#1002 · Langston#999 · Arden#1005 · Kabir#999 · Noa#1005 · Yeshua#1005 · Lev#999
Looking for what else is popular rather than what resembles Brennan? See the current top 100.
Choosing between Brennan and another name?
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US figures from the Social Security Administration. 1880–2025. Data & methodology
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