Explore the Family Name Brennan
The meaning of Brennan
Irish: 1. Anglicized form of Gaelic Ó Branáin or Mac Branáin ‘descendant (or son) of Branán’, a personal name meaning ‘little raven’. 2. Anglicized form of Ó Braonáin ‘descendant of Braonán’, a personal name based on a diminutive of braon ‘drop’. Compare Aubry 2. Some characteristic forenames: Irish Brendan, Ciaran, Kieran, Liam, Dermot, Eamon, Seamus, Siobhan, Brigid, Colm, Eamonn, Niall.
Dictionary of American Family Names, 2nd edition, © Oxford University Press, 2022.
How common is the last name Brennan in the United States?
The popularity of the surname Brennan has seen a slight fluctuation in recent years. According to data from the Decennial U.S. Census, in 2000, Brennan was the 642nd most common surname in the United States with a count of 48,296 people bearing the name. By 2010, the rank had dropped to 701 despite an increase in the overall number of Brennans to 49,238. This indicates that while the actual count of people named Brennan increased by 1.95%, its popularity decreased by 9.19% due to a larger growth of other surnames. The proportion per 100,000 people also dropped from 17.9 in 2000 to 16.69 in 2010, marking a change of -6.76%.
| 2000 | 2010 | Change | |
|---|---|---|---|
| Rank | #642 | #701 | -9.19% |
| Count | 48,296 | 49,238 | 1.95% |
| Proportion per 100k | 17.9 | 16.69 | -6.76% |
Race and Ethnicity of people with the last name Brennan
In terms of ethnicity, the majority of individuals with the surname Brennan identify as White, though there have been slight changes within this demographic over the years. Based on the Decennial U.S. Census, it can be noted that in 2000 around 95.97% identified as White, a figure that fell slightly to 94.56% in 2010. On the other hand, the percentage of Brennans who identify as Hispanic saw a significant increase from 1.5% in 2000 to 2.32% in 2010, marking a change of 54.67%. Similarly, the percentage of Asian/Pacific Islanders and those identifying as Black or belonging to two or more races rose by 40.68%, 15.94%, and 32.63% respectively. Meanwhile, the American Indian and Alaskan Native group saw a decrease in their representation among Brennans by 20%.
| 2000 | 2010 | Change | |
|---|---|---|---|
| White | 95.97% | 94.56% | -1.47% |
| Hispanic | 1.5% | 2.32% | 54.67% |
| Two or More Races | 0.95% | 1.26% | 32.63% |
| Asian/Pacific Islander | 0.59% | 0.83% | 40.68% |
| Black | 0.69% | 0.8% | 15.94% |
| American Indian and Alaskan Native | 0.3% | 0.24% | -20% |
Brennan ancestry composition
23andMe computes an ancestry breakdown for each customer. People may have ancestry from just one population or they may have ancestry from several populations. The most commonly-observed ancestry found in people with the surname Brennan is British & Irish, which comprises 61.6% of all ancestry found in people with the surname. The next two most common ancestries are French & German (14.9%) and Eastern European (6.7%). Additional ancestries include Italian, Scandinavian, Ashkenazi Jewish, Spanish & Portuguese, and Indigenous American.
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| ANCESTRY BREAKDOWN | COMPOSITION |
|---|---|
| British & Irish | 61.6% |
| French & German | 14.9% |
| Eastern European | 6.7% |
| Other | 16.8% |
Possible origins of the surname Brennan
Your DNA provides clues about where your recent ancestors may have lived. Having many distant relatives in the same location suggests that you may all share common ancestry there. Locations with many distant relatives can also be places where people have migrated recently, such as large cities. If a large number of individuals who share your surname have distant relatives in a specific area, it could indicate a connection between your surname and that location, stemming from either recent ancestral ties or migration.
Based on 23andMe data, people with last name Brennan have recent ancestry locations in the United Kingdom of Great Britain and Northern Ireland and Ireland.
| RECENT ANCESTRY Location | Percentage |
|---|---|
| Greater London, United Kingdom | 89.00% |
| Merseyside, United Kingdom | 88.90% |
| Greater Manchester, United Kingdom | 88.90% |
| Glasgow City, United Kingdom | 88.80% |
| West Midlands, United Kingdom | 88.20% |
What Brennan haplogroups can tell you
Haplogroups are genetic population groups that share a common ancestor on either your paternal or maternal line. These paternal and maternal haplogroups shed light on your genetic ancestry and help tell the story of your family.
The top paternal haplogroup of people with the surname Brennan is R-CTS241, which is predominantly found among people with European ancestry. Haplogroup R-CTS241 is descended from haplogroup R-M343. Other common haplogroups include R-L21 and R-S661, which are predominantly found among people with European and European ancestry. Other surnames with similar common haplogroups are: Mccarthy, Devine, Mcgowan, Cameron, Hughes, Duffy, Mcdonnell, Mccarty, Mcdonald, Keenan.
The most common maternal haplogroups of people with Brennan surname are: H1, T2b, H. These most commonly trace back to individuals of European ancestry.
Paternal Haplogroup Origins R-M343Your maternal lineage may be linked to Marie Antoinette
Because it is so dominant in the general European population, haplogroup H also appears quite frequently in the continent's royal houses. Marie Antoinette, an Austrian Hapsburg who married into the French royal family, inherited the haplogroup from her maternal ancestors. So did Prince Philip, Duke of Edinburgh, whose recorded genealogy traces his female line to Bavaria. Scientists also discovered that famed 16th century astronomer Nicolaus Copernicus traced his maternal lineages to haplogroup H.
What do people with the surname Brennan have in common?
Spoiler alert: it's complicated. People with the same last name are usually no more genetically similar than a randomly sampled group of people from the same population. That said, people with the same surname are more likely to have similar ancestries than randomly sampled individuals. The reason is the tendency of people with similar cultural or geographical backgrounds to preferentially mate with one another. That's why people who share a surname may be more likely to share traits and tendencies in common than people within the general population. Check out the percentages below to see the prevalences of tastes, habits, and traits of people with your surname compared with prevalences among 23andMe users.
Preferences
Chocolate Ice Cream
Prefers chocolate flavored ice cream over other flavors.
"Brennan" Surname 38.9%
23andMe Users 41.3%
Traits
Misophonia
When sounds made by others, like the sound of chewing or yawning, provoke strong emotional reactions in an individual.
"Brennan" Surname 27.7%
23andMe Users 27.9%
Habits
Sugary Drink
Drinks one or more sugary drinks per day.
"Brennan" Surname 18.2%
23andMe Users 21.1%
Wellness
Migraine
A severe headache characterized by intense pain, sensitivity to light and sound, and often accompanied by nausea and vomiting.
"Brennan" Surname 14.8%
23andMe Users 16.4%
Are health conditions linked to the last name Brennan?
The short answer is that, if there is an association between surname and health, it's usually more about your ancestry than your name. Individuals with a given surname are no more genetically similar than the general population but often have similar ancestries. The populations of people associated with those shared ancestries often have sets of genetic variations, also known as alleles, in common. Some of those alleles are associated with a greater likelihood of developing certain diseases.
Disease variant frequency by ancestry
Disease allele frequencies in populations associated with the surname Brennan are shown below. Important Note: not everyone with a disease allele will develop these health condition