How Many People Are Named Brennan?
An estimated 34,525 people in the United States have the first name Brennan. It is predominantly male (93.7%). The average bearer is 24 years old, and Brennan peaked in popularity in 2009 with 1,550 births that year.
Below you will find a full statistical profile of Brennan as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, and state-by-state birth registrations. You can also check how many people share the full name Brennan paired with any surname.
Estimated Living Americans
34,525
About 1 in 9,928 people in the U.S.
Rarity
Uncommon
Predicted Gender
Male
93.7% confidence
Average Age
24
years old
Peak Year
2009
1,550 births
Total Registered
35,250
since 1880
Gender Distribution for Brennan
Brennan is predominantly male (93.7%), though 2,218 female births have been registered. It functions as a unisex name for a small percentage of bearers.
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)
Brennan: Popularity Over Time
SSA records for Brennan span from the 1910s to the 2020s, covering 10 decades of naming data. The most popular decade for this name was the 2000s, when 12,394 babies were registered. Brennan has declined significantly from its peak in the 2000s. Recent registrations are a fraction of what they were at the name's height.
Brennan by Decade
How has Brennan tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Brennan by State
Birth registrations for Brennan span all 50 states and territories in the SSA database. The highest counts are in California, Texas, Louisiana. The lowest are in District of Columbia, Vermont, Delaware. On average, about 619 Brennans were registered per state.
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.
Names Similar to Brennan
Other first names starting with B with a similar number of bearers.
Brennan: Questions and Answers
How many people in the U.S. are named Brennan?
We estimate approximately 34,525 people named Brennan are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 9,928 Americans share this first name.
Is Brennan a common name?
Brennan is classified as "Uncommon" and is more popular than 98.9% of all first names in the SSA database. A total of 35,250 births have been registered with this name since 1880.
When was Brennan most popular?
Brennan reached peak popularity in 2009, when 1,550 babies were given this name. The average age of a living person named Brennan is approximately 24 years old, reflecting when the name was most commonly given.
Is Brennan a male name?
Brennan is predominantly male. 93.7% of people with this name are male. See the gender breakdown above for full details.
How many Brennan Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Brennan Smith, Brennan Johnson, Brennan Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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