2000
#1,938
National surname rank
Recorded bearers 17,027
First available Census row
Per 100,000 6.31
Uncommon Last name
Omalley
An Irish surname derived from the Gaelic "Ó Máille," meaning "descendant of Máille," a personal name meaning "prince."
According to the 2020 US Census Bureau surname tables, roughly 19,806 Americans carry the last name Omalley. That puts it at #2,045 in the national surname ranking, appearing at a frequency of 5.78 per 100,000 people (about 1 in 17,306 residents).
This page is the full Name Census profile for the Omalley 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 Omalley with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
20K
1 in 17,306
Census rank
#2,045
2020 decennial data
Per 100,000
5.8
Frequency rate
Recorded bearers
17K
uncommon in the US
Popularity narrative
The Census Bureau recorded 17,272 bearers of the surname Omalley in its 2020 decennial surname file. At a rate of 5.78 per 100,000 residents, it holds the 2045th position in the national surname ranking.
Among Census respondents with the surname Omalley, the largest self-reported group is White at 92.6%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%).
Origin
Meaning and origin of Omalley
The surname O'Malley is of Irish origin and has its roots in the Gaelic language. It is an anglicized version of the Irish Gaelic name "Ó Máille," which means "descendant of Máille." Máille was a personal name derived from the Old Irish word "máll," meaning "leader" or "prince."
The O'Malley family hailed from County Mayo in the western province of Connacht, Ireland. They were a prominent clan and held significant power in the region during the Middle Ages. The name is associated with the Barony of Murrisk, located in the coastal area of County Mayo.
Historical records indicate that the O'Malleys were a seafaring family and played a crucial role in maritime activities along the western coast of Ireland. In the 16th century, the clan was known for their involvement in piracy and their notorious exploits on the high seas.
One of the earliest recorded instances of the name O'Malley can be found in the Annals of the Four Masters, a historical chronicle compiled in the early 17th century. The annals mention several members of the O'Malley clan, including Grace O'Malley (c. 1530-c. 1603), a renowned Irish pirate queen, also known as "Gráinne Mhaol" or "Granuaile."
Another notable figure with the O'Malley surname was Owen Roe O'Malley (1598-1702), an Irish soldier who fought for the Spanish against the Dutch in the Low Countries during the Eighty Years' War. He later served in the Irish Confederate Wars and played a significant role in the Irish Rebellion of 1641.
In the 18th century, Theobald O'Malley (1720-1798) was an Irish priest and mathematician who made contributions to the field of calculus. He was a member of the Royal Irish Academy and served as a professor of mathematics at the University of Dublin.
During the 19th century, the surname O'Malley was associated with several prominent figures, including William Samuel O'Malley (1827-1904), an Irish-American businessman and politician who served as a member of the United States House of Representatives for New York.
Another notable individual with the O'Malley surname was Edward O'Malley (1842-1932), an American Roman Catholic priest and journalist. He served as the editor of the Catholic newspaper, The New World, and was instrumental in promoting Catholic education in the United States.
Demographics
Ancestry and ethnicity for Omalley
Among Census respondents with the surname Omalley, the largest self-reported group is White at 92.6%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%).
The bar chart below shows how Omalley 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 Omalley surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.6% · 15,986
- Hispanic or Latino3.1% · 544
- Two or more races2.9% · 499
- Asian and Pacific Islander0.8% · 131
- Black or African American0.5% · 78
- American Indian and Alaska Native0.2% · 34
Timeline
Historical Census data for Omalley
Omalley 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
#2,046
National surname rank
Recorded bearers 17,588
+561 bearers (+3.3%)
Per 100,000 5.96
Rank movement Down 108 places
2020
#2,045
National surname rank
Recorded bearers 17,272
-316 bearers (-1.8%)
Per 100,000 5.78
Rank movement Up 1 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #1,938 | 17,027 | 6.31 | First available Census row | First available Census row |
| 2010 | #2,046 | 17,588 | 5.96 | +561 bearers (+3.3%) | Down 108 places |
| 2020 | #2,045 | 17,272 | 5.78 | -316 bearers (-1.8%) | Up 1 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 Omalley 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 | #2,046 | #2,045 | 0.0% |
| Count | 17,588 | 17,272 | -1.8% |
| Per 100K | 5.96 | 5.78 | -3.0% |
Between the 2010 and 2020 Census, the number of Omalley bearers went from 17,588 to 17,272 (-1.8% change). The surname moved up 1 positions in the national ranking, going from #2,046 to #2,045.
FAQ
Omalley surname: questions and answers
How many people in the U.S. have the surname Omalley?
Name Census estimates that about 19,806 living Americans carry the surname Omalley. Using the current population baseline, that works out to roughly 1 in 17,306 residents.
How common is Omalley?
Omalley ranks #2,045 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 5.78 per 100,000 residents, which is about 6 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 17,272 people with the surname Omalley. That is different from the site's living-bearer estimate (19,806), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 5.78 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 5.78 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 6 of them to have the surname Omalley.
Has Omalley become more or less common over time?
Between 2010 and 2020, the surname Omalley went from 17,588 recorded bearers to 17,272. That is a decrease of 316 (-1.8%). In the national ranking it rose from #2,046 to #2,045.
What does the Census say about the background of Omalley?
Among Census respondents with the surname Omalley, the largest self-reported group is White at 92.6%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.9%). 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 Omalley in the 2020 Census, accounting for 92.6% (15,986 people in the source table).
What is the full ancestry breakdown?
Omalley appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.6%), Hispanic (3.1%), Two or More Races (2.9%). 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 Omalley (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 Omalley mean?
An Irish surname derived from the Gaelic "Ó Máille," meaning "descendant of Máille," a personal name meaning "prince." 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 Omalley (5.78 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 Omalley?
For a quick modern take, check how many people are called Omalley on our sister site HowManyOfMe.org.