2000
#135,837
National surname rank
Recorded bearers 114
First available Census row
Per 100,000 0.04
Very Rare Last name
Dermont
A surname derived from a French placename and possibly related to a fortified enclosure or castle.
According to the 2020 US Census Bureau surname tables, roughly 123 Americans carry the last name Dermont. That puts it at #151,639 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,786,621 residents).
This page is the full Name Census profile for the Dermont 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.
Bearers in the US
123
1 in 2,786,621
Census rank
#151,639
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
107
very rare in the US
Popularity narrative
The Census Bureau recorded 107 bearers of the surname Dermont in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 151639th position in the national surname ranking.
Among Census respondents with the surname Dermont, the largest self-reported group is White at 97.2%. The next largest groups are Asian/Pacific Islander (1.9%) and Hispanic (0.9%).
Origin
Meaning and origin of Dermont
The surname Dermont has its origins in Ireland, with records dating back to the 12th century. It is believed to be derived from the Irish Gaelic words "derb" meaning "sure" or "certain," and "mont" meaning "front" or "first." This suggests the name may have been initially used to describe someone who was the first or foremost in a particular activity or role.
One of the earliest recorded instances of the name can be found in the Annals of Ulster, a chronicle of medieval Irish history, which mentions a man named Dermont O'Conor in the year 1176. This individual was likely a member of the influential O'Conor dynasty, which ruled over the Kingdom of Connacht during that period.
In the 14th century, a Dermont O'Brien is recorded as having been the Bishop of Killaloe, a prominent religious figure in County Clare, Ireland. This suggests that the name was not exclusively associated with nobility but was also held by members of the clergy.
During the 16th century, the name Dermont appears in various legal documents and land records in counties such as Tipperary and Cork. This indicates that the surname was well-established across different regions of Ireland by this time.
One notable bearer of the name was Dermont O'Sullivan, who lived from 1536 to 1613. He was a renowned Irish military leader and chieftain who played a significant role in the Nine Years' War against English forces in Ireland.
Another prominent figure was Dermont O'Daly, born in 1619, who was a celebrated Irish poet and scholar. His works, written in both Irish and Latin, provide valuable insights into the cultural and literary traditions of his era.
In the 18th century, Dermont Murphy, born in 1733, was a respected Irish parliamentarian and landowner. He represented County Wexford in the Irish House of Commons and was known for his advocacy of tenant rights and agricultural reforms.
As the name Dermont spread beyond Ireland through emigration, it underwent various spelling variations, such as Dermond, Dermont, and Dermot. These variations can be found in historical records across different regions, reflecting the adaptations made by families as they settled in new areas.
While the surname Dermont may not be as common today as it once was, its deep roots in Irish history and the remarkable individuals who bore this name serve as a testament to its enduring legacy.
Demographics
Ancestry and ethnicity for Dermont
Among Census respondents with the surname Dermont, the largest self-reported group is White at 97.2%. The next largest groups are Asian/Pacific Islander (1.9%) and Hispanic (0.9%).
The bar chart below shows how Dermont 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 Dermont surname at the time of the 2020 Census, not any inherent property of the name itself.
- White97.2% · 104
- Asian and Pacific Islander1.9% · 2
- Hispanic or Latino0.9% · 1
Timeline
Historical Census data for Dermont
Dermont 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
#138,304
National surname rank
Recorded bearers 121
+7 bearers (+6.1%)
Per 100,000 0.04
Rank movement Down 2,467 places
2020
#151,639
National surname rank
Recorded bearers 107
-14 bearers (-11.6%)
Per 100,000 0.04
Rank movement Down 13,335 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #135,837 | 114 | 0.04 | First available Census row | First available Census row |
| 2010 | #138,304 | 121 | 0.04 | +7 bearers (+6.1%) | Down 2,467 places |
| 2020 | #151,639 | 107 | 0.04 | -14 bearers (-11.6%) | Down 13,335 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 Dermont 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 | #138,304 | #151,639 | -9.6% |
| Count | 121 | 107 | -11.6% |
| Per 100K | 0.04 | 0.04 | -10.5% |
Between the 2010 and 2020 Census, the number of Dermont bearers went from 121 to 107 (-11.6% change). The surname moved down 13,335 positions in the national ranking, going from #138,304 to #151,639.
FAQ
Dermont surname: questions and answers
How many people in the U.S. have the surname Dermont?
Name Census estimates that about 123 living Americans carry the surname Dermont. Using the current population baseline, that works out to roughly 1 in 2,786,621 residents.
How common is Dermont?
Dermont ranks #151,639 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.04 per 100,000 residents, which is about 0 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 107 people with the surname Dermont. That is different from the site's living-bearer estimate (123), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.04 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.04 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 0 of them to have the surname Dermont.
Has Dermont become more or less common over time?
Between 2010 and 2020, the surname Dermont went from 121 recorded bearers to 107. That is a decrease of 14 (-11.6%). In the national ranking it fell from #138,304 to #151,639.
What does the Census say about the background of Dermont?
Among Census respondents with the surname Dermont, the largest self-reported group is White at 97.2%. The next largest groups are Asian/Pacific Islander (1.9%) and Hispanic (0.9%). 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 Dermont in the 2020 Census, accounting for 97.2% (104 people in the source table).
What is the full ancestry breakdown?
Dermont appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (97.2%), Asian/Pacific Islander (1.9%), Hispanic (0.9%). 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 Dermont (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 Dermont mean?
A surname derived from a French placename and possibly related to a fortified enclosure or castle. 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 Dermont (0.04 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 Dermont?
For a quick modern take, check how many people have the last name Dermont on our sister site HowManyOfMe.org.