2000
#9,806
National surname rank
Recorded bearers 3,045
First available Census row
Per 100,000 1.13
Rare Last name
Oshaughnessy
A surname of Irish origin, derived from the Gaelic "Ó Seachnasaigh," meaning "descendant of Seachnasach," a personal name meaning "evasive" or "elusive."
According to the 2020 US Census Bureau surname tables, roughly 3,806 Americans carry the last name Oshaughnessy. That puts it at #9,396 in the national surname ranking, appearing at a frequency of 1.11 per 100,000 people (about 1 in 90,056 residents).
This page is the full Name Census profile for the Oshaughnessy 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 Oshaughnessy with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
3.8K
1 in 90,056
Census rank
#9,396
2020 decennial data
Per 100,000
1.1
Frequency rate
Recorded bearers
3.3K
rare in the US
Popularity narrative
The Census Bureau recorded 3,319 bearers of the surname Oshaughnessy in its 2020 decennial surname file. At a rate of 1.11 per 100,000 residents, it holds the 9396th position in the national surname ranking.
Among Census respondents with the surname Oshaughnessy, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (2.7%).
Origin
Meaning and origin of Oshaughnessy
The surname O'Shaughnessy is of Irish origin and can be traced back to the 12th century. It is derived from the Gaelic name 'Ó Seaghnaigh', which means 'descendant of Seaghanach'. The name Seaghanach itself is believed to have originated from the old Irish word 'seangan', meaning 'ant'.
The O'Shaughnessys were a prominent family in County Galway, Ireland, and their ancestral homeland was located in the ancient territory known as Cenél Áedha or Kinelea. This area encompassed parts of modern-day County Galway and County Roscommon. The name is also associated with the Baronies of Kinelea and Longford in County Galway.
One of the earliest recorded instances of the name O'Shaughnessy appears in the Annals of the Four Masters, a chronicle of medieval Irish history compiled in the 17th century. The annals mention an Aedh O'Shaughnessy who was slain in 1237 during a conflict between rival Irish clans.
In the 16th century, the O'Shaughnessy family was prominent in the region and held significant landholdings. Notable members from this period include Sir Roebuck O'Shaughnessy (c. 1566-1635), who was knighted by King James I of England, and his son Sir Roger O'Shaughnessy (c. 1600-1670), who served as a Colonel in the Irish Confederate Wars.
During the 17th and 18th centuries, the O'Shaughnessy name can be found in various legal documents and land records in County Galway. Some variations in spelling include O'Shaughnussey, O'Shaughnessy, and O'Shanecy.
In more recent history, several notable individuals have borne the O'Shaughnessy surname. These include Arthur O'Shaughnessy (1844-1881), an English poet known for his work "Ode" and his connections to the Pre-Raphaelite movement. Another prominent figure was Sir William O'Shaughnessy (1809-1889), an Irish physician who served as the Director-General of Telegraph Operations in British India and made significant contributions to the field of telegraphy.
Other notable O'Shaughnessys include Eliza O'Shaughnessy (1829-1900), an Irish-American religious leader and founder of the Sisters of Providence; Michael O'Shaughnessy (1864-1934), an Irish-American civil engineer who oversaw the construction of the Hetch Hetchy Reservoir in California; and James O'Shaughnessy (1810-1889), an Irish-American lawyer and politician who served as the United States Secretary of the Interior under President James Buchanan.
Demographics
Ancestry and ethnicity for Oshaughnessy
Among Census respondents with the surname Oshaughnessy, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (2.7%).
The bar chart below shows how Oshaughnessy 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 Oshaughnessy surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.2% · 3,059
- Hispanic or Latino3.7% · 124
- Two or more races2.7% · 88
- Black or African American0.7% · 24
- Asian and Pacific Islander0.7% · 24
Timeline
Historical Census data for Oshaughnessy
Oshaughnessy 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
#9,940
National surname rank
Recorded bearers 3,246
+201 bearers (+6.6%)
Per 100,000 1.10
Rank movement Down 134 places
2020
#9,396
National surname rank
Recorded bearers 3,319
+73 bearers (+2.2%)
Per 100,000 1.11
Rank movement Up 544 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #9,806 | 3,045 | 1.13 | First available Census row | First available Census row |
| 2010 | #9,940 | 3,246 | 1.10 | +201 bearers (+6.6%) | Down 134 places |
| 2020 | #9,396 | 3,319 | 1.11 | +73 bearers (+2.2%) | Up 544 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 Oshaughnessy 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 | #9,940 | #9,396 | 5.5% |
| Count | 3,246 | 3,319 | 2.2% |
| Per 100K | 1.10 | 1.11 | 0.9% |
Between the 2010 and 2020 Census, the number of Oshaughnessy bearers went from 3,246 to 3,319 (+2.2% change). The surname moved up 544 positions in the national ranking, going from #9,940 to #9,396.
FAQ
Oshaughnessy surname: questions and answers
How many people in the U.S. have the surname Oshaughnessy?
Name Census estimates that about 3,806 living Americans carry the surname Oshaughnessy. Using the current population baseline, that works out to roughly 1 in 90,056 residents.
How common is Oshaughnessy?
Oshaughnessy ranks #9,396 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.11 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 3,319 people with the surname Oshaughnessy. That is different from the site's living-bearer estimate (3,806), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.11 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.11 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 Oshaughnessy.
Has Oshaughnessy become more or less common over time?
Between 2010 and 2020, the surname Oshaughnessy went from 3,246 recorded bearers to 3,319. That is an increase of 73 (+2.2%). In the national ranking it rose from #9,940 to #9,396.
What does the Census say about the background of Oshaughnessy?
Among Census respondents with the surname Oshaughnessy, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (2.7%). 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 Oshaughnessy in the 2020 Census, accounting for 92.2% (3,059 people in the source table).
What is the full ancestry breakdown?
Oshaughnessy appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.2%), Hispanic (3.7%), Two or More Races (2.7%). 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 Oshaughnessy (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 Oshaughnessy mean?
A surname of Irish origin, derived from the Gaelic "Ó Seachnasaigh," meaning "descendant of Seachnasach," a personal name meaning "evasive" or "elusive." 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 Oshaughnessy (1.11 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 common is the surname Oshaughnessy?
See how common the surname Oshaughnessy is on HowManyOfMe.org, our sister site built around that single question.