2000
#9,036
National surname rank
Recorded bearers 3,326
First available Census row
Per 100,000 1.23
Rare Last name
Obrian
Anglicized form of the Irish surname Ó Briain, meaning "descendant of Brian," a name derived from an Old Celtic word for "high" or "noble."
According to the 2020 US Census Bureau surname tables, roughly 3,382 Americans carry the last name Obrian. That puts it at #10,391 in the national surname ranking, appearing at a frequency of 0.99 per 100,000 people (about 1 in 101,347 residents).
This page is the full Name Census profile for the Obrian surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
For British records, Name Census UK has a British surname profile for Obrian with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
3.4K
1 in 101,347
Census rank
#10,391
2020 decennial data
Per 100,000
1.0
Frequency rate
Recorded bearers
2.9K
rare in the US
Popularity narrative
The Census Bureau recorded 2,949 bearers of the surname Obrian in its 2020 decennial surname file. At a rate of 0.99 per 100,000 residents, it holds the 10391st position in the national surname ranking.
Among Census respondents with the surname Obrian, the largest self-reported group is White at 89.3%. The next largest groups are Hispanic (4.0%) and Black (3.0%).
Origin
Meaning and origin of Obrian
The surname OBRIAN has its origins in Ireland and is derived from the Gaelic personal name Ó Briain, meaning 'descendant of Brian'. The name Brian is a Celtic name meaning 'high' or 'noble'. The surname was originally found primarily in counties Clare and Tipperary.
The name can be traced back to the 10th century and the notable Brian Boru, an Irish king who reigned as High King of Ireland from 1002 until his death in 1014. Brian Boru is regarded as one of the most influential Irish monarchs and was known for his efforts to unite the Irish clans against the Vikings.
One of the earliest recorded examples of the surname OBRIAN appears in the Annals of Inisfallen, a chronicle of medieval Irish history dating back to the 11th century. The name is also found in the Annals of Ulster, another important historical source from the same period.
In the 13th century, the OBRIAN surname is recorded in the Pipe Rolls of Cloyne, which were records of taxation and land ownership in the diocese of Cloyne in County Cork. During this time, the surname was also associated with the Barony of Inchiquin in County Clare.
Throughout history, there have been several notable individuals with the surname OBRIAN. One of the most famous was Murrough O'Brien, 1st Earl of Thomond (1614-1674), an Irish nobleman and military leader who fought for the Royalists during the English Civil War.
Another was William Smith O'Brien (1803-1864), an Irish nationalist and revolutionary who led the Young Ireland movement and participated in the Irish Rebellion of 1848. He was convicted of sedition and transported to Van Diemen's Land (now Tasmania) before being pardoned in 1856.
In the realm of literature, Edna O'Brien (born 1930) is a renowned Irish novelist and memoirist, known for works such as "The Country Girls" and "The Little Red Chairs".
Other notable individuals with the surname include Lucius O'Brien (1800-1867), an Irish-American politician and lawyer who served as the 14th Mayor of New York City, and Conor Cruise O'Brien (1917-2008), an Irish diplomat, writer, and political theorist.
Demographics
Ancestry and ethnicity for Obrian
Among Census respondents with the surname Obrian, the largest self-reported group is White at 89.3%. The next largest groups are Hispanic (4.0%) and Black (3.0%).
The bar chart below shows how Obrian bearers 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 surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Obrian surname at the time of the 2020 Census, not any inherent property of the name itself.
- White89.3% · 2,632
- Hispanic or Latino4.0% · 117
- Black or African American3.0% · 88
- Two or more races2.7% · 80
- Asian and Pacific Islander0.9% · 27
- American Indian and Alaska Native0.2% · 5
Timeline
Historical Census data for Obrian
Obrian appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#10,064
National surname rank
Recorded bearers 3,203
-123 bearers (-3.7%)
Per 100,000 1.09
Rank movement Down 1,028 places
2020
#10,391
National surname rank
Recorded bearers 2,949
-254 bearers (-7.9%)
Per 100,000 0.99
Rank movement Down 327 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #9,036 | 3,326 | 1.23 | First available Census row | First available Census row |
| 2010 | #10,064 | 3,203 | 1.09 | -123 bearers (-3.7%) | Down 1,028 places |
| 2020 | #10,391 | 2,949 | 0.99 | -254 bearers (-7.9%) | Down 327 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Obrian surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #10,064 | #10,391 | -3.2% |
| Count | 3,203 | 2,949 | -7.9% |
| Per 100K | 1.09 | 0.99 | -9.5% |
Between the 2010 and 2020 Census, the number of Obrian bearers went from 3,203 to 2,949 (-7.9% change). The surname moved down 327 positions in the national ranking, going from #10,064 to #10,391.
Notable bearers
Famous people with the surname Obrian
FAQ
Obrian surname: questions and answers
How many people in the U.S. have the surname Obrian?
Name Census estimates that about 3,382 living Americans carry the surname Obrian. Using the current population baseline, that works out to roughly 1 in 101,347 residents.
How common is Obrian?
Obrian ranks #10,391 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.99 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 2,949 people with the surname Obrian. That is different from the site's living-bearer estimate (3,382), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.99 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.99 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Obrian.
Has Obrian become more or less common over time?
Between 2010 and 2020, the surname Obrian went from 3,203 recorded bearers to 2,949. That is a decrease of 254 (-7.9%). In the national ranking it fell from #10,064 to #10,391.
What does the Census say about the background of Obrian?
Among Census respondents with the surname Obrian, the largest self-reported group is White at 89.3%. The next largest groups are Hispanic (4.0%) and Black (3.0%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
White is the largest self-reported group for the surname Obrian in the 2020 Census, accounting for 89.3% (2,632 people in the source table).
What is the full ancestry breakdown?
Obrian appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (89.3%), Hispanic (4.0%), Black (3.0%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Obrian (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Obrian mean?
Anglicized form of the Irish surname Ó Briain, meaning "descendant of Brian," a name derived from an Old Celtic word for "high" or "noble." The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Obrian (0.99 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How many people are called Obrian?
You can see how many Americans have the surname Obrian on our sister site HowManyOfMe.org — same data roots, lighter UI.