2000
#4,101
National surname rank
Recorded bearers 7,996
First available Census row
Per 100,000 2.96
Rare Last name
Mahaffey
An Irish surname derived from the Gaelic "Ó Mothaigh," meaning "descendant of Mothaigh," a personal name meaning "proud" or "stately."
According to the 2020 US Census Bureau surname tables, roughly 8,767 Americans carry the last name Mahaffey. That puts it at #4,514 in the national surname ranking, appearing at a frequency of 2.56 per 100,000 people (about 1 in 39,096 residents).
This page is the full Name Census profile for the Mahaffey 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 Mahaffey with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
8.8K
1 in 39,096
Census rank
#4,514
2020 decennial data
Per 100,000
2.6
Frequency rate
Recorded bearers
7.6K
rare in the US
Popularity narrative
The Census Bureau recorded 7,645 bearers of the surname Mahaffey in its 2020 decennial surname file. At a rate of 2.56 per 100,000 residents, it holds the 4514th position in the national surname ranking.
Among Census respondents with the surname Mahaffey, the largest self-reported group is White at 87.6%. The next largest groups are Black (4.6%) and Two or More Races (3.5%).
Origin
Meaning and origin of Mahaffey
The surname MAHAFFEY is of Irish origin, with its roots traced back to the 16th century. It is believed to have originated from the Gaelic personal name "Mahon," which means "bear" or "great chief." The name is also closely associated with the County Monaghan region of Ireland.
One of the earliest recorded instances of the MAHAFFEY surname can be found in the Fiants of the Reign of Elizabeth I, a collection of official records from the 16th century. Here, the name appears as "Mahoffy" in reference to individuals residing in County Monaghan.
In the 17th century, the name MAHAFFEY began to appear in various historical documents, such as the Hearth Money Rolls of 1663-1665. These rolls were a form of tax record, providing valuable insights into the distribution and prevalence of surnames across Ireland during that period.
The MAHAFFEY surname has also been linked to the Gaelic word "Machaire," which means "plain" or "field." This connection suggests that the name may have originally referred to individuals who lived or worked on fertile plains or fields in County Monaghan.
One notable figure in history bearing the MAHAFFEY surname was William MAHAFFEY, an Irish-born soldier who served in the American Revolutionary War. Born in 1745 in County Monaghan, he emigrated to America and fought alongside the Continental Army, earning recognition for his bravery and leadership.
Another prominent individual with the MAHAFFEY surname was John MAHAFFEY, a prominent lawyer and politician in the early 19th century. Born in 1789 in County Monaghan, he served as a member of the Irish Parliament and was instrumental in advocating for Catholic emancipation and religious freedom.
In the late 18th and early 19th centuries, the MAHAFFEY surname began to appear in various records and documents across the United States, reflecting the emigration of Irish families bearing this name to the new world. One such example is James MAHAFFEY, a farmer and landowner born in 1780 in Pennsylvania, whose descendants spread across several states.
The MAHAFFEY surname has also been documented in various place names throughout Ireland, such as Mahaffey Bridge in County Monaghan and Mahaffey's Cross in County Fermanagh. These place names further underscore the deep roots and historical significance of this surname in the Irish landscape.
Throughout history, the MAHAFFEY surname has undergone various spelling variations, including Mahaffie, Mahaffy, Mahaffi, and Mahaffey. These variations often reflect regional dialects and the influence of different languages on the pronunciation and spelling of the name over time.
Demographics
Ancestry and ethnicity for Mahaffey
Among Census respondents with the surname Mahaffey, the largest self-reported group is White at 87.6%. The next largest groups are Black (4.6%) and Two or More Races (3.5%).
The bar chart below shows how Mahaffey 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 Mahaffey surname at the time of the 2020 Census, not any inherent property of the name itself.
- White87.6% · 6,696
- Black or African American4.6% · 355
- Two or more races3.5% · 266
- Hispanic or Latino3.4% · 261
- Asian and Pacific Islander0.5% · 37
- American Indian and Alaska Native0.4% · 30
Timeline
Historical Census data for Mahaffey
Mahaffey 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
#4,400
National surname rank
Recorded bearers 8,079
+83 bearers (+1.0%)
Per 100,000 2.74
Rank movement Down 299 places
2020
#4,514
National surname rank
Recorded bearers 7,645
-434 bearers (-5.4%)
Per 100,000 2.56
Rank movement Down 114 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #4,101 | 7,996 | 2.96 | First available Census row | First available Census row |
| 2010 | #4,400 | 8,079 | 2.74 | +83 bearers (+1.0%) | Down 299 places |
| 2020 | #4,514 | 7,645 | 2.56 | -434 bearers (-5.4%) | Down 114 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 Mahaffey 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 | #4,400 | #4,514 | -2.6% |
| Count | 8,079 | 7,645 | -5.4% |
| Per 100K | 2.74 | 2.56 | -6.7% |
Between the 2010 and 2020 Census, the number of Mahaffey bearers went from 8,079 to 7,645 (-5.4% change). The surname moved down 114 positions in the national ranking, going from #4,400 to #4,514.
FAQ
Mahaffey surname: questions and answers
How many people in the U.S. have the surname Mahaffey?
Name Census estimates that about 8,767 living Americans carry the surname Mahaffey. Using the current population baseline, that works out to roughly 1 in 39,096 residents.
How common is Mahaffey?
Mahaffey ranks #4,514 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 2.56 per 100,000 residents, which is about 3 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 7,645 people with the surname Mahaffey. That is different from the site's living-bearer estimate (8,767), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 2.56 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 2.56 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 3 of them to have the surname Mahaffey.
Has Mahaffey become more or less common over time?
Between 2010 and 2020, the surname Mahaffey went from 8,079 recorded bearers to 7,645. That is a decrease of 434 (-5.4%). In the national ranking it fell from #4,400 to #4,514.
What does the Census say about the background of Mahaffey?
Among Census respondents with the surname Mahaffey, the largest self-reported group is White at 87.6%. The next largest groups are Black (4.6%) 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 Mahaffey in the 2020 Census, accounting for 87.6% (6,696 people in the source table).
What is the full ancestry breakdown?
Mahaffey appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (87.6%), Black (4.6%), 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 Mahaffey (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 Mahaffey mean?
An Irish surname derived from the Gaelic "Ó Mothaigh," meaning "descendant of Mothaigh," a personal name meaning "proud" or "stately." 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 Mahaffey (2.56 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 are called Mahaffey?
Find out how many people have the surname Mahaffey on our sister site HowManyOfMe.org — a quick modern estimate with the living-bearer count front and centre.