2010
#145,220
National surname rank
Recorded bearers 114
First available Census row
Per 100,000 0.04
Very Rare Last name
Mcasey
An Anglicized form of the Gaelic surname Mac Oisdealbhaigh meaning "descendant of Oisdealbhach".
According to the 2020 US Census Bureau surname tables, roughly 136 Americans carry the last name Mcasey. That puts it at #142,788 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,520,252 residents).
This page is the full Name Census profile for the Mcasey 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.
Bearers in the US
136
1 in 2,520,252
Census rank
#142,788
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
119
very rare in the US
Popularity narrative
The Census Bureau recorded 119 bearers of the surname Mcasey in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 142788th position in the national surname ranking.
Among Census respondents with the surname Mcasey, the largest self-reported group is White at 89.1%. The next largest groups are Hispanic (4.2%) and Two or More Races (3.4%).
Origin
Meaning and origin of Mcasey
The surname MCASEY is of Irish origin, derived from the Gaelic personal name "Caisidhe" or "Caiside," which itself is derived from the old Irish word "cass" meaning "curved" or "twisted." The prefix "Mc" or "Mac" is a patronymic element meaning "son of," making the name MCASEY essentially "son of Caiside."
The name is thought to have originated in the northern regions of Ireland, particularly in counties such as Antrim, Derry, and Donegal. It first appeared in historical records in the 16th and 17th centuries, during the period of the Plantation of Ulster, when many Irish families were displaced from their ancestral lands.
One of the earliest documented instances of the name can be found in the Fiants of the Reign of Elizabeth I, which record a grant of land in County Antrim to a "Donnell McCassye" in 1588. The Annals of the Four Masters, a renowned chronicle of medieval Irish history, also mention a "Caiside Ó Doibhilin" (Caiside O'Devlin) who was slain in a battle in 1478.
In terms of notable individuals bearing the surname MCASEY, one of the earliest was John McCasey (c. 1600-1678), an Irish Catholic priest who served as the Vicar Apostolic of Clogher during the turbulent period of the Confederate Wars and the Cromwellian conquest of Ireland.
Another prominent figure was Terence MacCassy (c. 1640-1727), a Franciscan friar and historian who wrote extensively on the history of Irish monasteries and religious houses. His work, "The Emerald Mirror," is considered a valuable source of information on the Irish Catholic Church during the 17th century.
In more recent times, Hugh McCasey (1899-1993) was a renowned Irish politician and barrister who served as the Attorney General of Ireland from 1957 to 1961. He played a significant role in drafting the Republic of Ireland Act, which declared Ireland a republic in 1949.
Brendan McCasey (1927-2006) was an Irish actor and playwright, best known for his work in theater and television. He was a member of the prestigious Abbey Theatre company and appeared in several television series, including "The Riordans" and "Bracken."
Lastly, James McCasey (1938-2019) was a prominent figure in the Irish labor movement, serving as the General Secretary of the Irish Congress of Trade Unions from 1989 to 2001. He was widely respected for his advocacy of workers' rights and played a crucial role in various industrial disputes and negotiations.
Demographics
Ancestry and ethnicity for Mcasey
Among Census respondents with the surname Mcasey, the largest self-reported group is White at 89.1%. The next largest groups are Hispanic (4.2%) and Two or More Races (3.4%).
The bar chart below shows how Mcasey 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 Mcasey surname at the time of the 2020 Census, not any inherent property of the name itself.
- White89.1% · 106
- Hispanic or Latino4.2% · 5
- Two or more races3.4% · 4
- Black or African American2.5% · 3
- Asian and Pacific Islander0.8% · 1
Timeline
Historical Census data for Mcasey
Mcasey appears in 2 published Census surname files: 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2020
#142,788
National surname rank
Recorded bearers 119
+5 bearers (+4.4%)
Per 100,000 0.04
Rank movement Up 2,432 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2010 | #145,220 | 114 | 0.04 | First available Census row | First available Census row |
| 2020 | #142,788 | 119 | 0.04 | +5 bearers (+4.4%) | Up 2,432 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 Mcasey 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 | #145,220 | #142,788 | 1.7% |
| Count | 114 | 119 | 4.4% |
| Per 100K | 0.04 | 0.04 | -0.5% |
Between the 2010 and 2020 Census, the number of Mcasey bearers went from 114 to 119 (+4.4% change). The surname moved up 2,432 positions in the national ranking, going from #145,220 to #142,788.
FAQ
Mcasey surname: questions and answers
How many people in the U.S. have the surname Mcasey?
Name Census estimates that about 136 living Americans carry the surname Mcasey. Using the current population baseline, that works out to roughly 1 in 2,520,252 residents.
How common is Mcasey?
Mcasey ranks #142,788 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.04 per 100,000 residents, which is about 0 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 119 people with the surname Mcasey. That is different from the site's living-bearer estimate (136), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.04 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.04 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 0 of them to have the surname Mcasey.
Has Mcasey become more or less common over time?
Between 2010 and 2020, the surname Mcasey went from 114 recorded bearers to 119. That is an increase of 5 (+4.4%). In the national ranking it rose from #145,220 to #142,788.
What does the Census say about the background of Mcasey?
Among Census respondents with the surname Mcasey, the largest self-reported group is White at 89.1%. The next largest groups are Hispanic (4.2%) and Two or More Races (3.4%). 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 Mcasey in the 2020 Census, accounting for 89.1% (106 people in the source table).
What is the full ancestry breakdown?
Mcasey appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (89.1%), Hispanic (4.2%), Two or More Races (3.4%). 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 Mcasey (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 Mcasey mean?
An Anglicized form of the Gaelic surname Mac Oisdealbhaigh meaning "descendant of Oisdealbhach". 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 Mcasey (0.04 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 surname Mcasey?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.