2000
#7,411
National surname rank
Recorded bearers 4,148
First available Census row
Per 100,000 1.54
Rare Last name
Moynihan
Anglicized form of the Irish surname Ó Muimhneacháin, meaning "descendant of Muimhneachán," derived from the word "muimhneach," meaning "Munsterman."
According to the 2020 US Census Bureau surname tables, roughly 4,769 Americans carry the last name Moynihan. That puts it at #7,674 in the national surname ranking, appearing at a frequency of 1.39 per 100,000 people (about 1 in 71,871 residents).
This page is the full Name Census profile for the Moynihan 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 Moynihan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
4.8K
1 in 71,871
Census rank
#7,674
2020 decennial data
Per 100,000
1.4
Frequency rate
Recorded bearers
4.2K
rare in the US
Popularity narrative
The Census Bureau recorded 4,159 bearers of the surname Moynihan in its 2020 decennial surname file. At a rate of 1.39 per 100,000 residents, it holds the 7674th position in the national surname ranking.
Among Census respondents with the surname Moynihan, the largest self-reported group is White at 93.2%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.5%).
Origin
Meaning and origin of Moynihan
The surname Moynihan is of Irish origin and can be traced back to the 16th century. It is an Anglicized version of the Gaelic name Ó Muimhneacháin, which means "descendant of Muimhneachán". The name Muimhneachán is derived from the Irish word "muimhneach", meaning "hospitable" or "munificent".
The name Moynihan is predominantly found in the counties of Cork, Kerry, and Limerick in the southwestern part of Ireland. It is believed that the name originated in the region known as Munster, which was once a powerful kingdom in medieval Ireland.
One of the earliest recorded instances of the name can be found in the Annals of the Four Masters, a historical chronicle of medieval Irish history. The annals mention a Muimhneachán mac Duibhdhara, who was a celebrated Irish poet and historian in the 13th century.
In the 16th century, during the reign of Queen Elizabeth I, a certain Dermot Moynihan was noted as a member of the Irish nobility and a landowner in County Cork. This suggests that the Moynihan family held a significant social and political status at the time.
Another notable figure from history was Daniel Moynihan (1927-2003), an American politician, sociologist, and diplomat. He served as a United States Senator from New York and later as the United States Ambassador to the United Nations.
Other notable individuals with the surname Moynihan include:
1. Michael Moynihan (1670-1737), an Irish Catholic priest and Bishop of Killaloe.
2. Patrick Moynihan (1778-1825), an Irish rebel leader during the Irish Rebellion of 1798.
3. William Moynihan (1862-1936), an Irish-born Australian politician and member of the Australian Senate.
4. Mary Moynihan (1925-2021), an Irish actress and singer best known for her roles in various stage productions.
5. Colin Moynihan (born 1959), a British journalist and sports writer for The Telegraph.
The surname Moynihan has also been associated with various place names in Ireland, such as Moynihan's Cross, a townland in County Cork, and Moynihan's Well, a historic well located in County Kerry.
Demographics
Ancestry and ethnicity for Moynihan
Among Census respondents with the surname Moynihan, the largest self-reported group is White at 93.2%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.5%).
The bar chart below shows how Moynihan 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 Moynihan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White93.2% · 3,876
- Hispanic or Latino3.1% · 128
- Two or more races2.5% · 102
- Asian and Pacific Islander0.8% · 35
- Black or African American0.4% · 15
- American Indian and Alaska Native0.1% · 3
Timeline
Historical Census data for Moynihan
Moynihan 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
#7,627
National surname rank
Recorded bearers 4,352
+204 bearers (+4.9%)
Per 100,000 1.48
Rank movement Down 216 places
2020
#7,674
National surname rank
Recorded bearers 4,159
-193 bearers (-4.4%)
Per 100,000 1.39
Rank movement Down 47 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #7,411 | 4,148 | 1.54 | First available Census row | First available Census row |
| 2010 | #7,627 | 4,352 | 1.48 | +204 bearers (+4.9%) | Down 216 places |
| 2020 | #7,674 | 4,159 | 1.39 | -193 bearers (-4.4%) | Down 47 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 Moynihan 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 | #7,627 | #7,674 | -0.6% |
| Count | 4,352 | 4,159 | -4.4% |
| Per 100K | 1.48 | 1.39 | -6.0% |
Between the 2010 and 2020 Census, the number of Moynihan bearers went from 4,352 to 4,159 (-4.4% change). The surname moved down 47 positions in the national ranking, going from #7,627 to #7,674.
FAQ
Moynihan surname: questions and answers
How many people in the U.S. have the surname Moynihan?
Name Census estimates that about 4,769 living Americans carry the surname Moynihan. Using the current population baseline, that works out to roughly 1 in 71,871 residents.
How common is Moynihan?
Moynihan ranks #7,674 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.39 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 4,159 people with the surname Moynihan. That is different from the site's living-bearer estimate (4,769), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.39 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.39 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 Moynihan.
Has Moynihan become more or less common over time?
Between 2010 and 2020, the surname Moynihan went from 4,352 recorded bearers to 4,159. That is a decrease of 193 (-4.4%). In the national ranking it fell from #7,627 to #7,674.
What does the Census say about the background of Moynihan?
Among Census respondents with the surname Moynihan, the largest self-reported group is White at 93.2%. The next largest groups are Hispanic (3.1%) and Two or More Races (2.5%). 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 Moynihan in the 2020 Census, accounting for 93.2% (3,876 people in the source table).
What is the full ancestry breakdown?
Moynihan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (93.2%), Hispanic (3.1%), Two or More Races (2.5%). 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 Moynihan (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 Moynihan mean?
Anglicized form of the Irish surname Ó Muimhneacháin, meaning "descendant of Muimhneachán," derived from the word "muimhneach," meaning "Munsterman." 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 Moynihan (1.39 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 Moynihan?
Find out how many Americans have the surname Moynihan on our sister site HowManyOfMe.org — a quick modern estimate with the living-bearer count front and centre.