2000
#6,723
National surname rank
Recorded bearers 4,626
First available Census row
Per 100,000 1.71
Rare Last name
Killion
An Anglicized form of the Irish surname "Ó Cillín," meaning "descendant of Cillín," a personal name of uncertain origin.
According to the 2020 US Census Bureau surname tables, roughly 5,422 Americans carry the last name Killion. That puts it at #6,846 in the national surname ranking, appearing at a frequency of 1.58 per 100,000 people (about 1 in 63,215 residents).
This page is the full Name Census profile for the Killion 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
5.4K
1 in 63,215
Census rank
#6,846
2020 decennial data
Per 100,000
1.6
Frequency rate
Recorded bearers
4.7K
rare in the US
Popularity narrative
The Census Bureau recorded 4,728 bearers of the surname Killion in its 2020 decennial surname file. At a rate of 1.58 per 100,000 residents, it holds the 6846th position in the national surname ranking.
Among Census respondents with the surname Killion, the largest self-reported group is White at 84.5%. The next largest groups are Black (4.9%) and Two or More Races (4.0%).
Origin
Meaning and origin of Killion
The surname Killion is of Irish origin, with its roots traced back to the ancient Gaelic kingdom of Bréifne, which encompassed parts of modern-day counties Leitrim and Cavan. The name is derived from the Irish Gaelic "Ó Cillín," meaning "descendant of Cillín," a personal name meaning "little church" or "small monastery."
The earliest known record of the name dates back to the 12th century, when a certain Domhnall Ó Cillín was mentioned in the Annals of Ulster, a chronicle of medieval Irish history. This suggests that the Ó Cillín family held a prominent position in the region during that time.
In the 16th century, the name appeared in the Fiants of the Tudor Conquest, a collection of official documents from the reign of the Tudor monarchs in Ireland. This record mentions a grant of land to a Donough O'Killion in the county of Cavan.
One of the most notable figures bearing the Killion surname was Edmond Killion, a 17th-century Irish Catholic priest and historian. He authored the "Historiae Catholicae Iberniae Compendium," a comprehensive history of the Catholic Church in Ireland during the turbulent period of the Reformation.
Another prominent individual was Patrick Killion, an Irish revolutionary who fought alongside Wolfe Tone and the United Irishmen in the Irish Rebellion of 1798. He was captured and executed for his role in the rebellion.
In the 19th century, James Killion (1815-1887) was a successful businessman and entrepreneur from County Cavan who established a thriving shipping company in Liverpool, England.
The Killion surname has also been associated with several place names in Ireland, such as Killionmore and Killioneen, which are derived from the Irish words "cill" (church) and the family name itself.
Over the centuries, the spelling of the name has varied, with alternative forms including O'Killion, O'Killin, Killin, and Killian. However, the core meaning and lineage of the name have remained unchanged, tracing back to the ancient Irish kingdom of Bréifne and the descendants of Cillín.
Demographics
Ancestry and ethnicity for Killion
Among Census respondents with the surname Killion, the largest self-reported group is White at 84.5%. The next largest groups are Black (4.9%) and Two or More Races (4.0%).
The bar chart below shows how Killion 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 Killion surname at the time of the 2020 Census, not any inherent property of the name itself.
- White84.5% · 3,994
- Black or African American4.9% · 232
- Two or more races4.0% · 191
- Hispanic or Latino3.3% · 158
- Asian and Pacific Islander2.1% · 99
- American Indian and Alaska Native1.1% · 54
Timeline
Historical Census data for Killion
Killion 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
#6,799
National surname rank
Recorded bearers 4,960
+334 bearers (+7.2%)
Per 100,000 1.68
Rank movement Down 76 places
2020
#6,846
National surname rank
Recorded bearers 4,728
-232 bearers (-4.7%)
Per 100,000 1.58
Rank movement Down 47 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #6,723 | 4,626 | 1.71 | First available Census row | First available Census row |
| 2010 | #6,799 | 4,960 | 1.68 | +334 bearers (+7.2%) | Down 76 places |
| 2020 | #6,846 | 4,728 | 1.58 | -232 bearers (-4.7%) | 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 Killion 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 | #6,799 | #6,846 | -0.7% |
| Count | 4,960 | 4,728 | -4.7% |
| Per 100K | 1.68 | 1.58 | -5.8% |
Between the 2010 and 2020 Census, the number of Killion bearers went from 4,960 to 4,728 (-4.7% change). The surname moved down 47 positions in the national ranking, going from #6,799 to #6,846.
FAQ
Killion surname: questions and answers
How many people in the U.S. have the surname Killion?
Name Census estimates that about 5,422 living Americans carry the surname Killion. Using the current population baseline, that works out to roughly 1 in 63,215 residents.
How common is Killion?
Killion ranks #6,846 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.58 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 4,728 people with the surname Killion. That is different from the site's living-bearer estimate (5,422), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.58 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.58 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 Killion.
Has Killion become more or less common over time?
Between 2010 and 2020, the surname Killion went from 4,960 recorded bearers to 4,728. That is a decrease of 232 (-4.7%). In the national ranking it fell from #6,799 to #6,846.
What does the Census say about the background of Killion?
Among Census respondents with the surname Killion, the largest self-reported group is White at 84.5%. The next largest groups are Black (4.9%) and Two or More Races (4.0%). 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 Killion in the 2020 Census, accounting for 84.5% (3,994 people in the source table).
What is the full ancestry breakdown?
Killion appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (84.5%), Black (4.9%), Two or More Races (4.0%). 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 Killion (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 Killion mean?
An Anglicized form of the Irish surname "Ó Cillín," meaning "descendant of Cillín," a personal name of uncertain origin. 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 Killion (1.58 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 Killion?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.