2000
#631
National surname rank
Recorded bearers 48,833
First available Census row
Per 100,000 18.10
Uncommon Last name
Dillon
Derived from the Irish surname "O'Duilleain," meaning "descendant of Duilleán," a personal name meaning "little dark one" or "little blind one."
According to the 2020 US Census Bureau surname tables, roughly 54,776 Americans carry the last name Dillon. That puts it at #698 in the national surname ranking, appearing at a frequency of 15.98 per 100,000 people (about 1 in 6,257 residents).
This page is the full Name Census profile for the Dillon 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 Dillon with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
55K
1 in 6,257
Census rank
#698
2020 decennial data
Per 100,000
16.0
Frequency rate
Recorded bearers
48K
uncommon in the US
Popularity narrative
The Census Bureau recorded 47,767 bearers of the surname Dillon in its 2020 decennial surname file. At a rate of 15.98 per 100,000 residents, it holds the 698th position in the national surname ranking.
Among Census respondents with the surname Dillon, the largest self-reported group is White at 80.6%. The next largest groups are Black (10.3%) and Hispanic (3.6%).
Origin
Meaning and origin of Dillon
The surname Dillon has its origins in Ireland, where it emerged in the 12th century. It is an anglicized form of the Irish Gaelic name Ó Diolúin, which means "descendant of the grandson of Diolún." Diolún is a diminutive of the Irish word díol, meaning "payment" or "debt."
The Dillon family was among the Fourteen Tribes of Galway, a group of wealthy merchant families who held considerable power and influence in the city of Galway during the Middle Ages. The name first appeared in records in County Mayo, where the Dillons were a branch of the powerful Ó Conchubhair (O'Conor) dynasty.
One of the earliest recorded instances of the name is in the Annals of the Four Masters, a chronicle of medieval Irish history, which mentions a Conchobar Ó Diolúin in the year 1233. The name also appears in the Pipe Rolls of Cloyne, a collection of administrative records from the 13th century.
In the 14th century, the Dillons established themselves as Lords of Kilkenny West in County Westmeath. Notable members of the family from this period include Sir Henry Dillon (d. 1397), who served as Chief Governor of Ireland, and James Dillon (d. 1455), who was appointed Lord Chancellor of Ireland.
During the Tudor period, the Dillons played a significant role in Irish history. Gerald Dillon (1470-1538), known as the "Great Gerald," was a prominent figure in the Silken Thomas Rebellion against the English Crown. Another notable member of the family was Theobald Dillon (1530-1592), a Catholic martyr who was executed for his faith during the reign of Elizabeth I.
In the 17th century, Arthur Dillon (1670-1733) became a distinguished military commander in the service of France, rising to the rank of Marshal of France. His son, Théobald Dillon (1694-1777), also served in the French army and was created a Count of the Holy Roman Empire.
The 18th century saw the rise of John Dillon (1739-1809), a prominent Irish patriot and member of the United Irishmen. His son, John Blake Dillon (1814-1866), was a noted Irish nationalist and Member of Parliament who advocated for Irish independence.
Throughout its history, the surname Dillon has been associated with numerous prominent figures across various fields, including politics, military service, and literature. The name remains widely distributed in Ireland, particularly in the counties of Mayo, Westmeath, and Galway.
Demographics
Ancestry and ethnicity for Dillon
Among Census respondents with the surname Dillon, the largest self-reported group is White at 80.6%. The next largest groups are Black (10.3%) and Hispanic (3.6%).
The bar chart below shows how Dillon 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 Dillon surname at the time of the 2020 Census, not any inherent property of the name itself.
- White80.6% · 38,511
- Black or African American10.3% · 4,902
- Hispanic or Latino3.6% · 1,733
- Two or more races3.6% · 1,707
- American Indian and Alaska Native1.1% · 507
- Asian and Pacific Islander0.9% · 407
Timeline
Historical Census data for Dillon
Dillon 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
#683
National surname rank
Recorded bearers 50,465
+1,632 bearers (+3.3%)
Per 100,000 17.11
Rank movement Down 52 places
2020
#698
National surname rank
Recorded bearers 47,767
-2,698 bearers (-5.3%)
Per 100,000 15.98
Rank movement Down 15 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #631 | 48,833 | 18.10 | First available Census row | First available Census row |
| 2010 | #683 | 50,465 | 17.11 | +1,632 bearers (+3.3%) | Down 52 places |
| 2020 | #698 | 47,767 | 15.98 | -2,698 bearers (-5.3%) | Down 15 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 Dillon 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 | #683 | #698 | -2.2% |
| Count | 50,465 | 47,767 | -5.3% |
| Per 100K | 17.11 | 15.98 | -6.6% |
Between the 2010 and 2020 Census, the number of Dillon bearers went from 50,465 to 47,767 (-5.3% change). The surname moved down 15 positions in the national ranking, going from #683 to #698.
Notable bearers
Famous people with the surname Dillon
FAQ
Dillon surname: questions and answers
How many people in the U.S. have the surname Dillon?
Name Census estimates that about 54,776 living Americans carry the surname Dillon. Using the current population baseline, that works out to roughly 1 in 6,257 residents.
How common is Dillon?
Dillon ranks #698 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 15.98 per 100,000 residents, which is about 16 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 47,767 people with the surname Dillon. That is different from the site's living-bearer estimate (54,776), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 15.98 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 15.98 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 16 of them to have the surname Dillon.
Has Dillon become more or less common over time?
Between 2010 and 2020, the surname Dillon went from 50,465 recorded bearers to 47,767. That is a decrease of 2,698 (-5.3%). In the national ranking it fell from #683 to #698.
What does the Census say about the background of Dillon?
Among Census respondents with the surname Dillon, the largest self-reported group is White at 80.6%. The next largest groups are Black (10.3%) 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 Dillon in the 2020 Census, accounting for 80.6% (38,511 people in the source table).
What is the full ancestry breakdown?
Dillon appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (80.6%), Black (10.3%), 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 Dillon (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 Dillon mean?
Derived from the Irish surname "O'Duilleain," meaning "descendant of Duilleán," a personal name meaning "little dark one" or "little blind one." 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 Dillon (15.98 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 share the surname Dillon?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.