Brennan
A masculine given name of Irish origin meaning "descendant of the sorrow".
Name Census estimates that about 34,525 living Americans carry the first name Brennan. It is a predominantly male name (93.7% of registrations). The average person named Brennan today is around 24 years old, and the year with the single highest number of Brennan births was 2009 (1,550 babies).
This page is the full Name Census profile for Brennan. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Brennan with official rankings and popularity over time.
People living today
35K
~ 1 in 9,928 Americans
Peak year
2009
1,550 babies that year
Average age
24
years old
2024 SSA rank
#1,054
Tracked since 1916
Census
Brennan in the 2020 Census
The 2020 Census recorded 31,226 people with the first name Brennan, which placed it at #1,225 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#1,225
National first-name rank
People counted
31K
31,226 in the published race/origin table
Per 100,000
10.3
People with this name in 2020
Largest reported group
White
82.0% of people with this name
Demographics
Ancestry and ethnicity for Brennan
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Brennan is White at 82.0%. The next largest groups are Two or More Races (5.6%) and Hispanic (5.5%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Brennan described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Brennan at the time of the 2020 Census, not any inherent property of the name itself.
- White82.0% · 25,591
- Two or more races5.6% · 1,752
- Hispanic or Latino5.5% · 1,726
- Black or African American4.6% · 1,438
- Asian and Pacific Islander1.6% · 493
- American Indian and Alaska Native0.7% · 226
Gender
Gender distribution for Brennan
Brennan leans heavily male at 93.7% of total registrations, but 2,218 girls have also been registered with the name over the years, giving it a small but present crossover presence.
Brennan as a male name
- Ranked #1,054 in 2024
- 207 male births in 2024
- Peak: 2009 (1,464 births)
Brennan as a female name
- Ranked #6,414 in 2024
- 18 female births in 2024
- Peak: 2007 (100 births)
2020 Census snapshot
In the 2020 Census sex table, Brennan leans strongly male. 29,272 people counted with this name were male (93.8%), compared with 1,951 female bearers (6.2%).
Popularity
Brennan: popularity over time
The SSA tracks Brennan from the 1910s through to the 2020s, spanning 10 decades of birth certificate data. The biggest single decade for the name was the 2000s, with 12,394 total registrations. Usage has dropped considerably from its 2000s peak. The most recent decade brought in only a fraction of the registrations that the name once attracted.
Babies born per year
Decades
Brennan by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Brennan during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Brennans live
The SSA's state-level files cover 50 states and territories. California, Texas, Louisiana recorded the most babies named Brennan, while District of Columbia, Vermont, Delaware recorded the fewest. The average across all reporting states is about 619 registrations each.
Origin
Meaning and history of Brennan
The name Brennan has its origins in the Gaelic language, specifically in Irish Gaelic. It is derived from the Old Irish word "brennu," which means "a descendant of Bran." Bran is an ancient Celtic name that has been interpreted to mean "raven" or "crow."
The earliest recorded use of the name Brennan dates back to the 5th century AD in Ireland. It was originally a surname that eventually became adopted as a given name. The name was particularly popular among Irish families with connections to the ancient Irish kingdom of Leinster.
In Irish mythology, Bran is a prominent figure. He is featured in the Irish mythological cycle known as the "Fenian Cycle," which contains stories about the legendary hero Finn MacCool and his band of warriors called the Fianna. Bran is depicted as a powerful and wise leader.
One of the earliest recorded individuals with the name Brennan was Saint Brennan of Clonfert, who lived in the 6th century AD. He was an Irish monk and scholar who established numerous monasteries in Ireland and is credited with bringing Christianity to parts of the country.
Another notable historical figure with the name Brennan was Brennan of Armagh, who lived in the 7th century AD. He was a renowned Irish scholar and abbot who helped establish the monastic school at Armagh, which became a significant center of learning in medieval Europe.
In the 12th century, Brennan O'Rourke was a prominent Irish chieftain and military leader who fought against the Anglo-Norman invasion of Ireland. He was known for his bravery and resistance against the invading forces.
During the 16th century, Brennan Connell was an Irish poet and bard who composed numerous works in the Gaelic tradition. His poems and songs were widely appreciated and helped preserve Irish cultural heritage during a time of colonial oppression.
In more recent history, Brennan Manning (1934-2013) was an American author, theologian, and public speaker. He is best known for his influential book "The Ragamuffin Gospel," which explored the concept of God's unconditional love and grace.
People
Brennan + last name combinations
How many people share a full name with Brennan as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with B
Other first names starting with B with a similar number of bearers.
FAQ
Brennan: questions and answers
How many people in the U.S. are named Brennan?
Name Census puts the figure at roughly 34,525 living Americans. We arrive at this by taking every SSA birth registration for Brennan going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 9,928 US residents.
Is Brennan a common name?
We classify Brennan as "Uncommon". It ranks above 98.9% of all first names in the SSA dataset by living bearers. Across the full history of the data, 35,250 babies have been registered with this name.
When was Brennan most popular?
The single biggest year for Brennan was 2009, when 1,550 babies received the name. The fact that the average living Brennan is about 24 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Brennan in the 2020 Census?
The published 2020 Census first-name tables recorded 31,226 people with the name Brennan, or 10.34 per 100,000 residents. That placed it at #1,225 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Brennan in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Brennan?
In the 2020 Census sex table, Brennan leans strongly male. 29,272 people counted with this name were male (93.8%), compared with 1,951 female bearers (6.2%). The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Brennan?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Brennan is White at 82.0%. The next largest groups are Two or More Races (5.6%) and Hispanic (5.5%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Brennan most often in the Census?
White is the largest reported group for people named Brennan in the 2020 Census, accounting for 82.0% (25,591 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Brennan in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Brennan a male name?
Yes, 93.7% of people registered as Brennan in the SSA data are male. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Brennan still being used today?
Yes. The SSA still recorded Brennan in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Brennan can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many people have Brennan as a first name?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.