2000
#13,496
National surname rank
Recorded bearers 2,066
First available Census row
Per 100,000 0.77
Rare Last name
Lenihan
Derived from the Irish surname "Ó Leanacháin," meaning "descendant of Leanachán," a personal name meaning "lover" or "sweetheart."
According to the 2020 US Census Bureau surname tables, roughly 2,331 Americans carry the last name Lenihan. That puts it at #14,176 in the national surname ranking, appearing at a frequency of 0.68 per 100,000 people (about 1 in 147,042 residents).
This page is the full Name Census profile for the Lenihan 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 Lenihan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
2.3K
1 in 147,042
Census rank
#14,176
2020 decennial data
Per 100,000
0.7
Frequency rate
Recorded bearers
2.0K
rare in the US
Popularity narrative
The Census Bureau recorded 2,033 bearers of the surname Lenihan in its 2020 decennial surname file. At a rate of 0.68 per 100,000 residents, it holds the 14176th position in the national surname ranking.
Among Census respondents with the surname Lenihan, the largest self-reported group is White at 92.5%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.3%).
Origin
Meaning and origin of Lenihan
The surname Lenihan has its origins in Ireland and is believed to have first emerged in the 12th century. It is an Anglicized version of the Irish Gaelic name O'Lonáin, which is derived from the word "lonan," meaning "blackbird." This suggests that the name may have originally referred to someone with a dark complexion or dark hair.
The Lenihan name is primarily associated with County Cork in the southern part of Ireland, particularly in the region around the town of Macroom. However, it also has historical roots in other parts of Munster, including County Kerry and County Limerick.
One of the earliest recorded instances of the name Lenihan can be found in the Annals of Inisfallen, a chronicle of Irish history dating back to the 12th century. The annals mention a person named Diarmaid O'Lonáin, who was a notable figure in the region around Macroom in the late 12th century.
In the 16th century, the Lenihan family was among the most prominent septs (clans) in the Muskerry region of County Cork. They were closely associated with the MacCarthy clan, who were the ruling dynasty in the area at the time.
During the 17th century, several members of the Lenihan family played notable roles in the Irish Confederate Wars and the Williamite War in Ireland. One such individual was Donogh Lenihan, a captain in the Confederate Catholic forces who was killed in battle in 1646.
Throughout the 18th and 19th centuries, the Lenihan name continued to be prominent in County Cork and other parts of Munster. Notable individuals from this period include:
1. John Lenihan (1768-1848), an Irish Catholic landowner and Member of Parliament for the borough of Kilmallock.
2. Maurice Lenihan (1811-1854), an Irish historian and antiquarian who wrote extensively on the history and traditions of County Cork.
3. Patrick Lenihan (1815-1887), an Irish Catholic priest and writer who served as the Bishop of Killaloe.
4. Michael Lenihan (1889-1962), an Irish Fianna Fáil politician who served as Minister for Lands and later as a judge.
5. Brian Lenihan (1930-1995), an Irish Fianna Fáil politician who served as Minister for Foreign Affairs and later as Minister for Finance.
While the Lenihan name has its strongest historical roots in County Cork and Munster, it has also spread to other parts of Ireland and beyond over the centuries.
Demographics
Ancestry and ethnicity for Lenihan
Among Census respondents with the surname Lenihan, the largest self-reported group is White at 92.5%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.3%).
The bar chart below shows how Lenihan 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 Lenihan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.5% · 1,881
- Hispanic or Latino3.4% · 70
- Two or more races2.3% · 46
- Asian and Pacific Islander1.3% · 26
- Black or African American0.4% · 9
- American Indian and Alaska Native0.0% · 1
Timeline
Historical Census data for Lenihan
Lenihan 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
#14,119
National surname rank
Recorded bearers 2,128
+62 bearers (+3.0%)
Per 100,000 0.72
Rank movement Down 623 places
2020
#14,176
National surname rank
Recorded bearers 2,033
-95 bearers (-4.5%)
Per 100,000 0.68
Rank movement Down 57 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #13,496 | 2,066 | 0.77 | First available Census row | First available Census row |
| 2010 | #14,119 | 2,128 | 0.72 | +62 bearers (+3.0%) | Down 623 places |
| 2020 | #14,176 | 2,033 | 0.68 | -95 bearers (-4.5%) | Down 57 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 Lenihan 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 | #14,119 | #14,176 | -0.4% |
| Count | 2,128 | 2,033 | -4.5% |
| Per 100K | 0.72 | 0.68 | -5.5% |
Between the 2010 and 2020 Census, the number of Lenihan bearers went from 2,128 to 2,033 (-4.5% change). The surname moved down 57 positions in the national ranking, going from #14,119 to #14,176.
FAQ
Lenihan surname: questions and answers
How many people in the U.S. have the surname Lenihan?
Name Census estimates that about 2,331 living Americans carry the surname Lenihan. Using the current population baseline, that works out to roughly 1 in 147,042 residents.
How common is Lenihan?
Lenihan ranks #14,176 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.68 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 2,033 people with the surname Lenihan. That is different from the site's living-bearer estimate (2,331), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.68 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.68 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 Lenihan.
Has Lenihan become more or less common over time?
Between 2010 and 2020, the surname Lenihan went from 2,128 recorded bearers to 2,033. That is a decrease of 95 (-4.5%). In the national ranking it fell from #14,119 to #14,176.
What does the Census say about the background of Lenihan?
Among Census respondents with the surname Lenihan, the largest self-reported group is White at 92.5%. The next largest groups are Hispanic (3.4%) and Two or More Races (2.3%). 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 Lenihan in the 2020 Census, accounting for 92.5% (1,881 people in the source table).
What is the full ancestry breakdown?
Lenihan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.5%), Hispanic (3.4%), Two or More Races (2.3%). 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 Lenihan (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 Lenihan mean?
Derived from the Irish surname "Ó Leanacháin," meaning "descendant of Leanachán," a personal name meaning "lover" or "sweetheart." 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 Lenihan (0.68 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 Lenihan?
You can see how many people have the last name Lenihan on our sister site HowManyOfMe.org — same data roots, lighter UI.