Explore the Family Name Mcmahon

The meaning of Mcmahon

Irish: Anglicized form of Gaelic Mac Mathghamhna, a patronymic from the byname Mathghamhain literally meaning ‘good calf’, a kenning for ‘bear’. This was the name of two (unrelated) chieftain families in counties Clare (Thomond) and Monaghan (the kingdom of Oriel). See also Mahon 1, and Mahoney. In northern Ireland it is sometimes Anglicized as Matthews, since Matha was the Irish form of the Biblical name (see McMath). In Scotland Matheson was used to translate both of these surnames. Some characteristic forenames: Irish Brendan, Liam, Kieran, Maeve, Seamus, Brigid, Connor, Dermot, Eamon, Fergus, Grainne, James Patrick.

Dictionary of American Family Names, 2nd edition, © Oxford University Press, 2022.

How common is the last name Mcmahon in the United States?

Based on the Decennial U.S. Census data, the popularity of the surname McMahon has slightly decreased over a decade. In 2000, McMahon was ranked as the 819th most popular surname in the United States, with approximately 38,557 individuals carrying this family name, representing roughly 14.29 out of every 100,000 people. By 2010, although the count of individuals with the McMahon surname rose to around 39,411, its rank dropped to number 883 and the proportion per 100k people shrank to 13.36, marking a -7.81% change in rank and a -6.51% shift in proportion.

Proportion per 100k14.2913.36-6.51%

Race and Ethnicity of people with the last name Mcmahon

Analyzing the ethnicity associated with the surname McMahon, the data from the Decennial U.S. Census reveals intriguing trends between the years 2000 and 2010. The majority of McMahons were of White ethnic identity, showing a tiny decrease from 94.85% in 2000 to 93.22% in 2010. The percentage of McMahons who identified as Hispanic saw the most significant growth, jumping by 64.79% over the ten-year period. Both Asian/Pacific Islander and Two or more races identities also saw increases, moving up by 32.65% and 23.81% respectively. On the other hand, the fraction of McMahons identifying as American Indian and Alaskan Native slightly declined by 4.55%.

Two or More Races1.05%1.3%23.81%
Asian/Pacific Islander0.49%0.65%32.65%
American Indian and Alaskan Native0.22%0.21%-4.55%

Mcmahon ancestry composition

23andMe computes an ancestry breakdown for each customer. People may have ancestry from just one population or they may have ancestry from several populations. The most commonly-observed ancestry found in people with the surname Mcmahon is British & Irish, which comprises 60.1% of all ancestry found in people with the surname. The next two most common ancestries are French & German (15.6%) and Eastern European (6.3%). Additional ancestries include Italian, Scandinavian, Spanish & Portuguese, Ashkenazi Jewish, and Indigenous American.

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British & Irish60.1%
French & German15.6%
Eastern European6.3%

Possible origins of the surname Mcmahon

Your DNA provides clues about where your recent ancestors may have lived. Having many distant relatives in the same location suggests that you may all share common ancestry there. Locations with many distant relatives can also be places where people have migrated recently, such as large cities. If a large number of individuals who share your surname have distant relatives in a specific area, it could indicate a connection between your surname and that location, stemming from either recent ancestral ties or migration.

Based on 23andMe data, people with last name Mcmahon have recent ancestry locations in the United Kingdom of Great Britain and Northern Ireland and Ireland.

RECENT ANCESTRY LocationPercentage
Greater Manchester, United Kingdom87.10%
Greater London, United Kingdom87.10%
Glasgow City, United Kingdom87.00%
Merseyside, United Kingdom86.80%
West Midlands, United Kingdom86.20%

What Mcmahon haplogroups can tell you

Haplogroups are genetic population groups that share a common ancestor on either your paternal or maternal line. These paternal and maternal haplogroups shed light on your genetic ancestry and help tell the story of your family.

The top paternal haplogroup of people with the surname Mcmahon is R-CTS241, which is predominantly found among people with European ancestry. Haplogroup R-CTS241 is descended from haplogroup R-M343. Other common haplogroups include R-L21 and R-Z255, which are predominantly found among people with European and European ancestry. Other surnames with similar common haplogroups are: Murphy, Walsh, Mccarthy, Mahoney, Dempsey, Hughes, Griffiths, Cameron, Whalen, Conner.

The most common maternal haplogroups of people with Mcmahon surname are: H1, T2b, H. These most commonly trace back to individuals of European ancestry.

mcmahonPaternal Haplogroup Origins R-M343

Your maternal lineage may be linked to Marie Antoinette

Because it is so dominant in the general European population, haplogroup H also appears quite frequently in the continent's royal houses. Marie Antoinette, an Austrian Hapsburg who married into the French royal family, inherited the haplogroup from her maternal ancestors. So did Prince Philip, Duke of Edinburgh, whose recorded genealogy traces his female line to Bavaria. Scientists also discovered that famed 16th century astronomer Nicolaus Copernicus traced his maternal lineages to haplogroup H.

Maternal Haplo Image

What do people with the surname Mcmahon have in common?

Spoiler alert: it's complicated. People with the same last name are usually no more genetically similar than a randomly sampled group of people from the same population. That said, people with the same surname are more likely to have similar ancestries than randomly sampled individuals. The reason is the tendency of people with similar cultural or geographical backgrounds to preferentially mate with one another. That's why people who share a surname may be more likely to share traits and tendencies in common than people within the general population. Check out the percentages below to see the prevalences of tastes, habits, and traits of people with your surname compared with prevalences among 23andMe users.



Chocolate Ice Cream

Prefers chocolate flavored ice cream over other flavors.

"Mcmahon" Surname 46.0%

23andMe Users 41.3%




When sounds made by others, like the sound of chewing or yawning, provoke strong emotional reactions in an individual.

"Mcmahon" Surname 29.3%

23andMe Users 27.9%



Sugary Drink

Drinks one or more sugary drinks per day.

"Mcmahon" Surname 21.0%

23andMe Users 21.1%




A severe headache characterized by intense pain, sensitivity to light and sound, and often accompanied by nausea and vomiting.

"Mcmahon" Surname 16.5%

23andMe Users 16.4%

Are health conditions linked to the last name Mcmahon?

The short answer is that, if there is an association between surname and health, it's usually more about your ancestry than your name. Individuals with a given surname are no more genetically similar than the general population but often have similar ancestries. The populations of people associated with those shared ancestries often have sets of genetic variations, also known as alleles, in common. Some of those alleles are associated with a greater likelihood of developing certain diseases.

Disease variant frequency by ancestry

Disease allele frequencies in populations associated with the surname Mcmahon are shown below. Important Note: not everyone with a disease allele will develop these health condition

Age-Related Macular Degeneration

Y402H variant

Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss among older adults. The disease results in damage to the central part of the retina (the macula), impairing vision needed for reading, driving, or even recognizing faces. The 23andMe Health + Ancestry DNA test includes the two most common variants associated with an increased risk of developing the condition: the Y402H variant in the CFH gene and the A69S variant in the ARMS2 gene. Learn more about Age-Related Macular Degeneration

British & Irish 62.1%

23andMe Users 57.2%