2000
#5,614
National surname rank
Recorded bearers 5,668
First available Census row
Per 100,000 2.10
Rare Last name
Kiernan
A surname of Irish origin, derived from the Gaelic "Ó Ciaráin," meaning "descendant of Ciarán" (little dark one).
According to the 2020 US Census Bureau surname tables, roughly 6,456 Americans carry the last name Kiernan. That puts it at #5,900 in the national surname ranking, appearing at a frequency of 1.88 per 100,000 people (about 1 in 53,091 residents).
This page is the full Name Census profile for the Kiernan 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 Kiernan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
6.5K
1 in 53,091
Census rank
#5,900
2020 decennial data
Per 100,000
1.9
Frequency rate
Recorded bearers
5.6K
rare in the US
Popularity narrative
The Census Bureau recorded 5,630 bearers of the surname Kiernan in its 2020 decennial surname file. At a rate of 1.88 per 100,000 residents, it holds the 5900th position in the national surname ranking.
Among Census respondents with the surname Kiernan, the largest self-reported group is White at 91.8%. The next largest groups are Hispanic (4.2%) and Two or More Races (2.6%).
Origin
Meaning and origin of Kiernan
The surname Kiernan is of Irish origin, derived from the Gaelic personal name Ciarán, meaning "little dark one" or "little tanned one." It is believed to have originated in the 5th century AD in the ancient Irish kingdom of Meath.
The name Ciarán was borne by several early Irish saints, the most famous being St. Ciarán of Clonmacnoise (516-549 AD), who founded the influential monastery of Clonmacnoise in County Offaly. The Kiernan surname is thought to have emerged from this monastic settlement, as families often adopted the names of revered saints.
One of the earliest recorded instances of the Kiernan surname appears in the Annals of the Four Masters, a chronicle of medieval Irish history, which mentions a "Kiernan O'Melaghlin" in the year 1236. This suggests that the surname had become established by the 13th century.
Throughout the Middle Ages, the Kiernans were a prominent family in the Irish midlands, particularly in Counties Westmeath and Longford. The name is also associated with the ancient territory of Fir Chennada, located in what is now County Leitrim.
Notable historical figures with the Kiernan surname include Geoffrey Kiernan (1595-1675), an Irish Catholic priest and author who was a prominent figure in the Confederate War in Ireland. Another was Matthias Kiernan (1804-1875), an Irish-born American Catholic priest who founded several churches and schools in the Diocese of Richmond, Virginia.
In the 19th century, James Kiernan (1819-1890) was a successful Irish-American businessman and philanthropist in New York City, known for his support of Catholic charities and educational institutions. Mary Kiernan (1889-1982), born in Ireland, was a prominent labor activist and organizer who worked tirelessly for the rights of garment workers in New York City.
The Kiernan name has also been associated with various place names in Ireland, such as Kiernansgrove in County Leitrim and Kiernans Bridge in County Westmeath, reflecting the historical presence of the family in these regions.
Demographics
Ancestry and ethnicity for Kiernan
Among Census respondents with the surname Kiernan, the largest self-reported group is White at 91.8%. The next largest groups are Hispanic (4.2%) and Two or More Races (2.6%).
The bar chart below shows how Kiernan 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 Kiernan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White91.8% · 5,167
- Hispanic or Latino4.2% · 236
- Two or more races2.6% · 149
- Asian and Pacific Islander1.0% · 57
- Black or African American0.3% · 18
- American Indian and Alaska Native0.1% · 3
Timeline
Historical Census data for Kiernan
Kiernan 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
#5,802
National surname rank
Recorded bearers 5,966
+298 bearers (+5.3%)
Per 100,000 2.02
Rank movement Down 188 places
2020
#5,900
National surname rank
Recorded bearers 5,630
-336 bearers (-5.6%)
Per 100,000 1.88
Rank movement Down 98 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #5,614 | 5,668 | 2.10 | First available Census row | First available Census row |
| 2010 | #5,802 | 5,966 | 2.02 | +298 bearers (+5.3%) | Down 188 places |
| 2020 | #5,900 | 5,630 | 1.88 | -336 bearers (-5.6%) | Down 98 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 Kiernan 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 | #5,802 | #5,900 | -1.7% |
| Count | 5,966 | 5,630 | -5.6% |
| Per 100K | 2.02 | 1.88 | -6.8% |
Between the 2010 and 2020 Census, the number of Kiernan bearers went from 5,966 to 5,630 (-5.6% change). The surname moved down 98 positions in the national ranking, going from #5,802 to #5,900.
FAQ
Kiernan surname: questions and answers
How many people in the U.S. have the surname Kiernan?
Name Census estimates that about 6,456 living Americans carry the surname Kiernan. Using the current population baseline, that works out to roughly 1 in 53,091 residents.
How common is Kiernan?
Kiernan ranks #5,900 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.88 per 100,000 residents, which is about 2 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 5,630 people with the surname Kiernan. That is different from the site's living-bearer estimate (6,456), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.88 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.88 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 2 of them to have the surname Kiernan.
Has Kiernan become more or less common over time?
Between 2010 and 2020, the surname Kiernan went from 5,966 recorded bearers to 5,630. That is a decrease of 336 (-5.6%). In the national ranking it fell from #5,802 to #5,900.
What does the Census say about the background of Kiernan?
Among Census respondents with the surname Kiernan, the largest self-reported group is White at 91.8%. The next largest groups are Hispanic (4.2%) and Two or More Races (2.6%). 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 Kiernan in the 2020 Census, accounting for 91.8% (5,167 people in the source table).
What is the full ancestry breakdown?
Kiernan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (91.8%), Hispanic (4.2%), Two or More Races (2.6%). 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 Kiernan (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 Kiernan mean?
A surname of Irish origin, derived from the Gaelic "Ó Ciaráin," meaning "descendant of Ciarán" (little dark one). 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 Kiernan (1.88 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 Kiernan?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.