2000
#2,356
National surname rank
Recorded bearers 14,071
First available Census row
Per 100,000 5.22
Uncommon Last name
Mcmahan
Irish: descendant of Mathghamhain, a derivative of the Old Irish name Mathgamain, meaning "bear" or "calf."
According to the 2020 US Census Bureau surname tables, roughly 15,497 Americans carry the last name Mcmahan. That puts it at #2,608 in the national surname ranking, appearing at a frequency of 4.52 per 100,000 people (about 1 in 22,117 residents).
This page is the full Name Census profile for the Mcmahan 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 Mcmahan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
15K
1 in 22,117
Census rank
#2,608
2020 decennial data
Per 100,000
4.5
Frequency rate
Recorded bearers
14K
uncommon in the US
Popularity narrative
The Census Bureau recorded 13,514 bearers of the surname Mcmahan in its 2020 decennial surname file. At a rate of 4.52 per 100,000 residents, it holds the 2608th position in the national surname ranking.
Among Census respondents with the surname Mcmahan, the largest self-reported group is White at 88.7%. The next largest groups are Two or More Races (3.9%) and Black (3.3%).
Origin
Meaning and origin of Mcmahan
The surname McMahan originated in Scotland and Ireland during the medieval period. It is a patronymic surname derived from the Gaelic personal name "MacMathghamhna," which means "son of the bear." This name likely referred to a person with a bear-like appearance or characteristics.
The earliest recorded instances of the surname McMahan can be found in Scottish and Irish records from the 13th and 14th centuries. The name was particularly prevalent in the Scottish Highlands and the northern counties of Ireland, where it was often spelled as "MacMaughan," "MacMahon," or "MacMathghamhna."
One of the earliest known bearers of the name was Domhnall MacMathghamhna, who was a Scottish chieftain from Argyll in the early 14th century. He is mentioned in the Annals of Ulster, a chronicle of medieval Irish history.
In the 15th century, the McMahan surname appeared in several legal documents and land charters in the counties of Antrim and Down in Northern Ireland. One notable example is Seamus MacMaughan, who was granted lands in Antrim in the 1460s.
During the 16th and 17th centuries, many McMahans migrated from Scotland and Ireland to other parts of the British Isles, as well as to the American colonies. One of the earliest recorded McMahans in America was John McMahan, who arrived in Pennsylvania in the late 17th century.
Other notable bearers of the McMahan surname throughout history include:
1. Sir Brian MacMahon (c. 1480-1552), an Irish chieftain and leader of the MacMahon clan in County Monaghan.
2. Hugh McMahan (1695-1769), an Irish-born American surveyor and pioneer who helped establish the city of Pittsburgh, Pennsylvania.
3. John McMahan (1756-1824), an American Revolutionary War soldier and early settler in Kentucky.
4. Bernard McMahan (1810-1887), an Irish-born Australian politician and member of the Legislative Council of New South Wales.
5. James McMahan (1820-1885), an American Civil War soldier who was awarded the Medal of Honor for his actions at the Battle of Jonesboro.
The McMahan surname has also been associated with various place names, particularly in Ireland, where it was common in counties like Monaghan, Fermanagh, and Tyrone. Examples include the townlands of McMahon's Quarter and McMahon's Island.
Demographics
Ancestry and ethnicity for Mcmahan
Among Census respondents with the surname Mcmahan, the largest self-reported group is White at 88.7%. The next largest groups are Two or More Races (3.9%) and Black (3.3%).
The bar chart below shows how Mcmahan 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 Mcmahan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White88.7% · 11,986
- Two or more races3.9% · 533
- Black or African American3.3% · 440
- Hispanic or Latino2.7% · 363
- American Indian and Alaska Native0.9% · 125
- Asian and Pacific Islander0.5% · 67
Timeline
Historical Census data for Mcmahan
Mcmahan 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
#2,522
National surname rank
Recorded bearers 14,368
+297 bearers (+2.1%)
Per 100,000 4.87
Rank movement Down 166 places
2020
#2,608
National surname rank
Recorded bearers 13,514
-854 bearers (-5.9%)
Per 100,000 4.52
Rank movement Down 86 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #2,356 | 14,071 | 5.22 | First available Census row | First available Census row |
| 2010 | #2,522 | 14,368 | 4.87 | +297 bearers (+2.1%) | Down 166 places |
| 2020 | #2,608 | 13,514 | 4.52 | -854 bearers (-5.9%) | Down 86 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 Mcmahan 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 | #2,522 | #2,608 | -3.4% |
| Count | 14,368 | 13,514 | -5.9% |
| Per 100K | 4.87 | 4.52 | -7.2% |
Between the 2010 and 2020 Census, the number of Mcmahan bearers went from 14,368 to 13,514 (-5.9% change). The surname moved down 86 positions in the national ranking, going from #2,522 to #2,608.
FAQ
Mcmahan surname: questions and answers
How many people in the U.S. have the surname Mcmahan?
Name Census estimates that about 15,497 living Americans carry the surname Mcmahan. Using the current population baseline, that works out to roughly 1 in 22,117 residents.
How common is Mcmahan?
Mcmahan ranks #2,608 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 4.52 per 100,000 residents, which is about 5 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 13,514 people with the surname Mcmahan. That is different from the site's living-bearer estimate (15,497), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 4.52 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 4.52 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 5 of them to have the surname Mcmahan.
Has Mcmahan become more or less common over time?
Between 2010 and 2020, the surname Mcmahan went from 14,368 recorded bearers to 13,514. That is a decrease of 854 (-5.9%). In the national ranking it fell from #2,522 to #2,608.
What does the Census say about the background of Mcmahan?
Among Census respondents with the surname Mcmahan, the largest self-reported group is White at 88.7%. The next largest groups are Two or More Races (3.9%) and Black (3.3%). 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 Mcmahan in the 2020 Census, accounting for 88.7% (11,986 people in the source table).
What is the full ancestry breakdown?
Mcmahan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (88.7%), Two or More Races (3.9%), Black (3.3%). 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 Mcmahan (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 Mcmahan mean?
Irish: descendant of Mathghamhain, a derivative of the Old Irish name Mathgamain, meaning "bear" or "calf." 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 Mcmahan (4.52 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 Mcmahan?
If you just want to know how many people have the surname Mcmahan, HowManyOfMe.org gives you the headline number in one glance.