2000
#3,054
National surname rank
Recorded bearers 10,879
First available Census row
Per 100,000 4.03
Uncommon Last name
Osullivan
A Irish surname meaning "descendant of Súileabhán," an Irish name combining the elements "súil" (eye) and "dubh" (dark).
According to the 2020 US Census Bureau surname tables, roughly 13,727 Americans carry the last name Osullivan. That puts it at #2,941 in the national surname ranking, appearing at a frequency of 4.01 per 100,000 people (about 1 in 24,969 residents).
This page is the full Name Census profile for the Osullivan 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 Osullivan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
14K
1 in 24,969
Census rank
#2,941
2020 decennial data
Per 100,000
4.0
Frequency rate
Recorded bearers
12K
uncommon in the US
Popularity narrative
The Census Bureau recorded 11,971 bearers of the surname Osullivan in its 2020 decennial surname file. At a rate of 4.01 per 100,000 residents, it holds the 2941st position in the national surname ranking.
Among Census respondents with the surname Osullivan, the largest self-reported group is White at 91.1%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.8%).
Origin
Meaning and origin of Osullivan
The surname OSULLIVAN originated in Ireland and dates back to the 10th century. It is an Anglicized form of the Irish Gaelic name Ó Súilleabháin, which means "descendant of Súilleabhán". The prefix "Ó" indicates "grandson" or "descendant".
The name is derived from the Old Irish personal name Súilleabhán, which is a compound of the elements "súil" meaning "eye" and "leabhán" meaning "little calf". This suggests that the original bearer of the name may have had some distinctive eye features or was particularly observant.
OSULLIVAN is a prominent surname in Ireland, particularly in the counties of Cork and Kerry. The name first appears in the Annals of Inisfallen, a chronicle of medieval Irish history, in the year 1028.
One of the earliest recorded bearers of the name was Domhnall Ó Súilleabháin, who was the chief of the OSULLIVAN clan in the 14th century. The clan was based in the Beara Peninsula and the Iveragh Peninsula in County Kerry.
In the 16th century, Donal Cam O'Sullivan Beare was a prominent leader of the O'Sullivan Beare clan during the Elizabethan conquest of Ireland. He led the famous O'Sullivan Beare's march in 1602, a remarkable 600-mile journey through the winter wilderness to seek refuge in Ulster.
Other notable figures with the surname OSULLIVAN include Theobald O'Sullivan, an Irish Jesuit and philosopher (1548-1608), and Owen Roe O'Sullivan, an Irish military leader who fought for the Catholic Confederation during the Irish Confederate Wars (1604-1657).
In the 18th century, Seán Ó Súilleabháin was a renowned Irish poet and scribe, also known as John O'Sullivan (1752-1809). Seamus Osullivan, an Irish writer and journalist, was born in 1879 and is known for his contributions to the Irish literary revival.
The name OSULLIVAN has also been carried by notable figures outside of Ireland, such as John L. O'Sullivan, an American writer and editor who coined the phrase "Manifest Destiny" in 1845, advocating for the annexation of Texas and the Oregon Country.
Demographics
Ancestry and ethnicity for Osullivan
Among Census respondents with the surname Osullivan, the largest self-reported group is White at 91.1%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.8%).
The bar chart below shows how Osullivan 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 Osullivan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White91.1% · 10,903
- Hispanic or Latino3.4% · 409
- Two or more races2.8% · 340
- Black or African American1.7% · 201
- Asian and Pacific Islander0.9% · 107
- American Indian and Alaska Native0.1% · 11
Timeline
Historical Census data for Osullivan
Osullivan 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
#3,032
National surname rank
Recorded bearers 11,818
+939 bearers (+8.6%)
Per 100,000 4.01
Rank movement Up 22 places
2020
#2,941
National surname rank
Recorded bearers 11,971
+153 bearers (+1.3%)
Per 100,000 4.01
Rank movement Up 91 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #3,054 | 10,879 | 4.03 | First available Census row | First available Census row |
| 2010 | #3,032 | 11,818 | 4.01 | +939 bearers (+8.6%) | Up 22 places |
| 2020 | #2,941 | 11,971 | 4.01 | +153 bearers (+1.3%) | Up 91 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 Osullivan 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 | #3,032 | #2,941 | 3.0% |
| Count | 11,818 | 11,971 | 1.3% |
| Per 100K | 4.01 | 4.01 | -0.1% |
Between the 2010 and 2020 Census, the number of Osullivan bearers went from 11,818 to 11,971 (+1.3% change). The surname moved up 91 positions in the national ranking, going from #3,032 to #2,941.
Notable bearers
Famous people with the surname Osullivan
FAQ
Osullivan surname: questions and answers
How many people in the U.S. have the surname Osullivan?
Name Census estimates that about 13,727 living Americans carry the surname Osullivan. Using the current population baseline, that works out to roughly 1 in 24,969 residents.
How common is Osullivan?
Osullivan ranks #2,941 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 4.01 per 100,000 residents, which is about 4 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 11,971 people with the surname Osullivan. That is different from the site's living-bearer estimate (13,727), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 4.01 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 4.01 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 4 of them to have the surname Osullivan.
Has Osullivan become more or less common over time?
Between 2010 and 2020, the surname Osullivan went from 11,818 recorded bearers to 11,971. That is an increase of 153 (+1.3%). In the national ranking it rose from #3,032 to #2,941.
What does the Census say about the background of Osullivan?
Among Census respondents with the surname Osullivan, the largest self-reported group is White at 91.1%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.8%). 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 Osullivan in the 2020 Census, accounting for 91.1% (10,903 people in the source table).
What is the full ancestry breakdown?
Osullivan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (91.1%), Hispanic (3.4%), Two or More Races (2.8%). 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 Osullivan (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 Osullivan mean?
A Irish surname meaning "descendant of Súileabhán," an Irish name combining the elements "súil" (eye) and "dubh" (dark). 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 Osullivan (4.01 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 have the last name Osullivan?
For a quick modern take, check how many Americans have the surname Osullivan on our sister site HowManyOfMe.org.