2000
#827
National surname rank
Recorded bearers 37,962
First available Census row
Per 100,000 14.07
Uncommon Last name
Duffy
Derived from the Irish Ó Dubhthaigh, meaning "descendant of Dubhthach," a personal name composed of the elements dubh, meaning "black," and tach, meaning "peace."
According to the 2020 US Census Bureau surname tables, roughly 43,066 Americans carry the last name Duffy. That puts it at #915 in the national surname ranking, appearing at a frequency of 12.56 per 100,000 people (about 1 in 7,959 residents).
This page is the full Name Census profile for the Duffy 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 Duffy with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
43K
1 in 7,959
Census rank
#915
2020 decennial data
Per 100,000
12.6
Frequency rate
Recorded bearers
38K
uncommon in the US
Popularity narrative
The Census Bureau recorded 37,556 bearers of the surname Duffy in its 2020 decennial surname file. At a rate of 12.56 per 100,000 residents, it holds the 915th position in the national surname ranking.
Among Census respondents with the surname Duffy, the largest self-reported group is White at 88.1%. The next largest groups are Black (4.1%) and Hispanic (3.6%).
Origin
Meaning and origin of Duffy
The surname Duffy originated from Ireland and can be traced back to the 12th century. It is derived from the Irish Gaelic name 'Ó Dubhthaigh', which means 'descendant of Dubhthach', a personal name meaning 'black' or 'swarthy'.
The Duffy surname was primarily found in the counties of Monaghan, Cavan, and Leitrim in the northern part of Ireland. It is believed that the name originated in the territory of Bréifne, which was ruled by the Uí Briúin dynasty.
In the Annals of Ulster, a historical record of medieval Irish events, there are several references to individuals with the name Dubhthaigh or Duffy. For example, in the year 1197, the death of Gilla Criost Ua Dubhthaigh, a notable cleric, is recorded.
One of the earliest known examples of the Duffy surname is found in the Annals of the Four Masters, a chronicle of medieval Irish history, which mentions Maolmordha Ua Dubhthaigh, who died in 1022.
The Duffy name is also linked to several place names in Ireland, such as Duffy's Cross in County Cavan and Duffy's Hill in County Monaghan.
Notable individuals with the Duffy surname include:
1. Sir Charles Gavan Duffy (1816-1903), an Irish politician and author who played a significant role in the Young Ireland movement.
2. William Duffy (1842-1912), an Irish-American politician and businessman who served as the 28th Mayor of Chicago from 1893 to 1895.
3. James Duffy (1888-1969), an Irish-born American prelate who served as the Bishop of Grand Island from 1948 to 1959.
4. Brian Duffy (1933-2010), an English painter and photographer known for his iconic portraits of celebrities in the 1960s and 1970s.
5. Maureen Duffy (born 1933), an English poet, novelist, and playwright, best known for her novel "The Microcosm" and her involvement in the feminist movement.
The Duffy surname has a rich history rooted in Ireland, with references dating back to the 12th century and spanning various historical records, notable individuals, and place names.
Demographics
Ancestry and ethnicity for Duffy
Among Census respondents with the surname Duffy, the largest self-reported group is White at 88.1%. The next largest groups are Black (4.1%) and Hispanic (3.6%).
The bar chart below shows how Duffy 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 Duffy surname at the time of the 2020 Census, not any inherent property of the name itself.
- White88.1% · 33,089
- Black or African American4.1% · 1,537
- Hispanic or Latino3.6% · 1,348
- Two or more races2.8% · 1,056
- Asian and Pacific Islander0.9% · 350
- American Indian and Alaska Native0.5% · 176
Timeline
Historical Census data for Duffy
Duffy 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
#892
National surname rank
Recorded bearers 38,835
+873 bearers (+2.3%)
Per 100,000 13.17
Rank movement Down 65 places
2020
#915
National surname rank
Recorded bearers 37,556
-1,279 bearers (-3.3%)
Per 100,000 12.56
Rank movement Down 23 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #827 | 37,962 | 14.07 | First available Census row | First available Census row |
| 2010 | #892 | 38,835 | 13.17 | +873 bearers (+2.3%) | Down 65 places |
| 2020 | #915 | 37,556 | 12.56 | -1,279 bearers (-3.3%) | Down 23 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 Duffy 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 | #892 | #915 | -2.6% |
| Count | 38,835 | 37,556 | -3.3% |
| Per 100K | 13.17 | 12.56 | -4.6% |
Between the 2010 and 2020 Census, the number of Duffy bearers went from 38,835 to 37,556 (-3.3% change). The surname moved down 23 positions in the national ranking, going from #892 to #915.
Notable bearers
Famous people with the surname Duffy
FAQ
Duffy surname: questions and answers
How many people in the U.S. have the surname Duffy?
Name Census estimates that about 43,066 living Americans carry the surname Duffy. Using the current population baseline, that works out to roughly 1 in 7,959 residents.
How common is Duffy?
Duffy ranks #915 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 12.56 per 100,000 residents, which is about 13 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 37,556 people with the surname Duffy. That is different from the site's living-bearer estimate (43,066), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 12.56 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 12.56 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 13 of them to have the surname Duffy.
Has Duffy become more or less common over time?
Between 2010 and 2020, the surname Duffy went from 38,835 recorded bearers to 37,556. That is a decrease of 1,279 (-3.3%). In the national ranking it fell from #892 to #915.
What does the Census say about the background of Duffy?
Among Census respondents with the surname Duffy, the largest self-reported group is White at 88.1%. The next largest groups are Black (4.1%) and Hispanic (3.6%). 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 Duffy in the 2020 Census, accounting for 88.1% (33,089 people in the source table).
What is the full ancestry breakdown?
Duffy appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (88.1%), Black (4.1%), Hispanic (3.6%). 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 Duffy (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 Duffy mean?
Derived from the Irish Ó Dubhthaigh, meaning "descendant of Dubhthach," a personal name composed of the elements dubh, meaning "black," and tach, meaning "peace." 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 Duffy (12.56 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 Americans have the surname Duffy?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.