2000
#4,537
National surname rank
Recorded bearers 7,177
First available Census row
Per 100,000 2.66
Rare Last name
Carnahan
An Irish surname derived from the Gaelic "Ó Cearnachain," meaning "descendant of Cearnachán" (a personal name of uncertain meaning).
According to the 2020 US Census Bureau surname tables, roughly 8,137 Americans carry the last name Carnahan. That puts it at #4,828 in the national surname ranking, appearing at a frequency of 2.37 per 100,000 people (about 1 in 42,123 residents).
This page is the full Name Census profile for the Carnahan 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
8.1K
1 in 42,123
Census rank
#4,828
2020 decennial data
Per 100,000
2.4
Frequency rate
Recorded bearers
7.1K
rare in the US
Popularity narrative
The Census Bureau recorded 7,096 bearers of the surname Carnahan in its 2020 decennial surname file. At a rate of 2.37 per 100,000 residents, it holds the 4828th position in the national surname ranking.
Among Census respondents with the surname Carnahan, the largest self-reported group is White at 91.0%. The next largest groups are Hispanic (3.5%) and Two or More Races (3.5%).
Origin
Meaning and origin of Carnahan
The surname Carnahan is believed to have originated in Ireland, where it was derived from the Gaelic words "carn" and "áth," meaning "cairn" (a man-made stack of stones) and "ford" or "river crossing," respectively. This suggests that the name may have initially referred to a person who lived near a cairn and a river crossing.
The earliest recorded instances of the Carnahan surname can be traced back to the 16th century in County Antrim, Northern Ireland. It is likely that the name was initially anglicized from its Gaelic roots during this period, resulting in various spellings such as Carnahan, Carnaghan, and Carnaghyn.
In the 17th century, the name appears in the Fiants of the Reign of Elizabeth, a collection of official records from the Irish Court of Chancery. Entries from this period mention individuals with the surname Carnahan residing in County Antrim and surrounding areas.
One notable individual bearing the Carnahan surname was John Carnahan (1629-1698), a Presbyterian minister and one of the first settlers in the Bann Valley region of County Londonderry, Ireland. He is credited with establishing several churches in the area and played a significant role in the religious life of the community.
During the 18th century, many Carnahans emigrated from Ireland to North America, particularly to the American colonies and regions of present-day Canada. One such individual was James Carnahan (1751-1832), a soldier who fought in the American Revolutionary War and later settled in Pennsylvania.
In the 19th century, the Carnahan surname gained further prominence with individuals like Robert Carnahan (1801-1868), an American lawyer and politician who served as a judge in Ohio and as a member of the United States Congress.
Another notable figure was William Carnahan (1820-1890), a Scottish-born American Presbyterian minister and educator who served as the president of the College of New Jersey (now Princeton University) from 1868 to 1883.
Throughout history, the Carnahan surname has been associated with various professions, including clergy, military, law, and education, reflecting the diverse backgrounds and contributions of those who have borne this name.
Demographics
Ancestry and ethnicity for Carnahan
Among Census respondents with the surname Carnahan, the largest self-reported group is White at 91.0%. The next largest groups are Hispanic (3.5%) and Two or More Races (3.5%).
The bar chart below shows how Carnahan 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 Carnahan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White91.0% · 6,455
- Hispanic or Latino3.5% · 251
- Two or more races3.5% · 247
- Black or African American0.8% · 55
- Asian and Pacific Islander0.7% · 52
- American Indian and Alaska Native0.5% · 36
Timeline
Historical Census data for Carnahan
Carnahan 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
#4,769
National surname rank
Recorded bearers 7,424
+247 bearers (+3.4%)
Per 100,000 2.52
Rank movement Down 232 places
2020
#4,828
National surname rank
Recorded bearers 7,096
-328 bearers (-4.4%)
Per 100,000 2.37
Rank movement Down 59 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #4,537 | 7,177 | 2.66 | First available Census row | First available Census row |
| 2010 | #4,769 | 7,424 | 2.52 | +247 bearers (+3.4%) | Down 232 places |
| 2020 | #4,828 | 7,096 | 2.37 | -328 bearers (-4.4%) | Down 59 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 Carnahan 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 | #4,769 | #4,828 | -1.2% |
| Count | 7,424 | 7,096 | -4.4% |
| Per 100K | 2.52 | 2.37 | -5.8% |
Between the 2010 and 2020 Census, the number of Carnahan bearers went from 7,424 to 7,096 (-4.4% change). The surname moved down 59 positions in the national ranking, going from #4,769 to #4,828.
Notable bearers
Famous people with the surname Carnahan
FAQ
Carnahan surname: questions and answers
How many people in the U.S. have the surname Carnahan?
Name Census estimates that about 8,137 living Americans carry the surname Carnahan. Using the current population baseline, that works out to roughly 1 in 42,123 residents.
How common is Carnahan?
Carnahan ranks #4,828 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 2.37 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 7,096 people with the surname Carnahan. That is different from the site's living-bearer estimate (8,137), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 2.37 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 2.37 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 Carnahan.
Has Carnahan become more or less common over time?
Between 2010 and 2020, the surname Carnahan went from 7,424 recorded bearers to 7,096. That is a decrease of 328 (-4.4%). In the national ranking it fell from #4,769 to #4,828.
What does the Census say about the background of Carnahan?
Among Census respondents with the surname Carnahan, the largest self-reported group is White at 91.0%. The next largest groups are Hispanic (3.5%) and Two or More Races (3.5%). 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 Carnahan in the 2020 Census, accounting for 91.0% (6,455 people in the source table).
What is the full ancestry breakdown?
Carnahan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (91.0%), Hispanic (3.5%), Two or More Races (3.5%). 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 Carnahan (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 Carnahan mean?
An Irish surname derived from the Gaelic "Ó Cearnachain," meaning "descendant of Cearnachán" (a personal name of uncertain meaning). 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 Carnahan (2.37 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 Carnahan?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.