2000
#13,791
National surname rank
Recorded bearers 2,013
First available Census row
Per 100,000 0.75
Rare Last name
Calahan
An Anglicized form of the Irish surname "Ó Ceallacháin," meaning "descendant of Ceallachán" (a personal name meaning "bright-headed").
According to the 2020 US Census Bureau surname tables, roughly 2,182 Americans carry the last name Calahan. That puts it at #14,921 in the national surname ranking, appearing at a frequency of 0.64 per 100,000 people (about 1 in 157,083 residents).
This page is the full Name Census profile for the Calahan 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 Calahan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
2.2K
1 in 157,083
Census rank
#14,921
2020 decennial data
Per 100,000
0.6
Frequency rate
Recorded bearers
1.9K
rare in the US
Popularity narrative
The Census Bureau recorded 1,903 bearers of the surname Calahan in its 2020 decennial surname file. At a rate of 0.64 per 100,000 residents, it holds the 14921st position in the national surname ranking.
Among Census respondents with the surname Calahan, the largest self-reported group is White at 70.3%. The next largest groups are Black (21.9%) and Two or More Races (3.8%).
Origin
Meaning and origin of Calahan
The surname Calahan has its origins in the Gaelic language and is believed to have emerged in Ireland during the medieval period. It is thought to be derived from the Irish words "calath" and "an," which collectively translate to "the battle" or "the strife." This suggests that the name may have been initially bestowed upon an individual or family with a reputation for being formidable warriors or embroiled in conflicts.
Historically, the name Calahan was most prevalent in the counties of Donegal, Galway, and Mayo in Ireland. Some of the earliest recorded instances of the name can be found in ancient Irish manuscripts and chronicles dating back to the 12th century, where it appears with various spelling variations such as Callaghan, Callaghen, and Callachan.
One notable historical figure bearing the Calahan surname was Dermot Calahan, a chieftain from Donegal who fought alongside the Irish forces during the Nine Years' War (1594-1603) against English rule. Another prominent individual was Rory Calahan, born in 1688, who was a renowned Irish scholar and poet renowned for his contributions to preserving the Gaelic language and culture.
In the annals of Irish history, the name Calahan is also associated with several place names, such as Calahan's Castle in County Mayo, which was once the stronghold of a powerful Calahan clan in the region. Additionally, the town of Calahan's Cross in County Galway is believed to have been named after a prominent Calahan family who resided there in the 16th century.
During the mass emigration of Irish people to the United States and other parts of the world in the 19th century, many individuals bearing the Calahan surname left their homeland in search of better opportunities. Among the notable Calahans of this era was Michael Calahan, born in 1822, who became a successful businessman and philanthropist in New York City.
Another individual of historical significance was Margaret Calahan (1848-1924), a pioneering educator who established several schools in the American West and played a pivotal role in promoting education for Native American children. Similarly, John Calahan (1861-1932), a railway engineer, was instrumental in the construction of several major railroad lines across the United States, contributing significantly to the nation's infrastructure development.
Demographics
Ancestry and ethnicity for Calahan
Among Census respondents with the surname Calahan, the largest self-reported group is White at 70.3%. The next largest groups are Black (21.9%) and Two or More Races (3.8%).
The bar chart below shows how Calahan 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 Calahan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White70.3% · 1,338
- Black or African American21.9% · 417
- Two or more races3.8% · 73
- Hispanic or Latino3.3% · 62
- Asian and Pacific Islander0.5% · 9
- American Indian and Alaska Native0.2% · 4
Timeline
Historical Census data for Calahan
Calahan 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
#13,713
National surname rank
Recorded bearers 2,207
+194 bearers (+9.6%)
Per 100,000 0.75
Rank movement Up 78 places
2020
#14,921
National surname rank
Recorded bearers 1,903
-304 bearers (-13.8%)
Per 100,000 0.64
Rank movement Down 1,208 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #13,791 | 2,013 | 0.75 | First available Census row | First available Census row |
| 2010 | #13,713 | 2,207 | 0.75 | +194 bearers (+9.6%) | Up 78 places |
| 2020 | #14,921 | 1,903 | 0.64 | -304 bearers (-13.8%) | Down 1,208 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 Calahan 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 | #13,713 | #14,921 | -8.8% |
| Count | 2,207 | 1,903 | -13.8% |
| Per 100K | 0.75 | 0.64 | -15.1% |
Between the 2010 and 2020 Census, the number of Calahan bearers went from 2,207 to 1,903 (-13.8% change). The surname moved down 1,208 positions in the national ranking, going from #13,713 to #14,921.
FAQ
Calahan surname: questions and answers
How many people in the U.S. have the surname Calahan?
Name Census estimates that about 2,182 living Americans carry the surname Calahan. Using the current population baseline, that works out to roughly 1 in 157,083 residents.
How common is Calahan?
Calahan ranks #14,921 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.64 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 1,903 people with the surname Calahan. That is different from the site's living-bearer estimate (2,182), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.64 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.64 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 Calahan.
Has Calahan become more or less common over time?
Between 2010 and 2020, the surname Calahan went from 2,207 recorded bearers to 1,903. That is a decrease of 304 (-13.8%). In the national ranking it fell from #13,713 to #14,921.
What does the Census say about the background of Calahan?
Among Census respondents with the surname Calahan, the largest self-reported group is White at 70.3%. The next largest groups are Black (21.9%) and Two or More Races (3.8%). 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 Calahan in the 2020 Census, accounting for 70.3% (1,338 people in the source table).
What is the full ancestry breakdown?
Calahan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (70.3%), Black (21.9%), Two or More Races (3.8%). 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 Calahan (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 Calahan mean?
An Anglicized form of the Irish surname "Ó Ceallacháin," meaning "descendant of Ceallachán" (a personal name meaning "bright-headed"). 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 Calahan (0.64 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 Americans have the surname Calahan?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.