2000
#1,086
National surname rank
Recorded bearers 29,440
First available Census row
Per 100,000 10.91
Uncommon Last name
Mcdermott
Derived from the Gaelic "Mac Diarmada," meaning "son of Diarmaid," a popular Irish personal name meaning "free from envy."
According to the 2020 US Census Bureau surname tables, roughly 34,180 Americans carry the last name Mcdermott. That puts it at #1,157 in the national surname ranking, appearing at a frequency of 9.97 per 100,000 people (about 1 in 10,028 residents).
This page is the full Name Census profile for the Mcdermott 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 Mcdermott with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
34K
1 in 10,028
Census rank
#1,157
2020 decennial data
Per 100,000
10.0
Frequency rate
Recorded bearers
30K
uncommon in the US
Popularity narrative
The Census Bureau recorded 29,807 bearers of the surname Mcdermott in its 2020 decennial surname file. At a rate of 9.97 per 100,000 residents, it holds the 1157th position in the national surname ranking.
Among Census respondents with the surname Mcdermott, the largest self-reported group is White at 89.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (3.2%).
Origin
Meaning and origin of Mcdermott
The surname McDermott is of Irish origin, derived from the Gaelic name Mac Diarmada, meaning "son of Diarmaid." Diarmaid was a personal name derived from the Old Irish words "diar," meaning "free," and "maid," meaning "lord" or "chief." The name is believed to have originated in the 10th or 11th century in the Irish counties of Roscommon and Sligo.
The McDermott family was a prominent clan in the region of Connacht, particularly in the area now known as County Roscommon. One of the earliest recorded references to the name is in the Annals of the Four Masters, a chronicle of medieval Irish history compiled in the early 17th century. The Annals mention several members of the McDermott clan, including Tomaltach Mac Diarmada, who was chief of the clan in the late 12th century.
In the 13th century, the McDermott clan was among the Irish families who resisted the Norman invasion and continued to hold significant territory in Connacht. During this period, the name appeared in various forms, such as Mac Diarmata and MacDermot, reflecting the changing spelling conventions of the time.
One of the most notable figures in the history of the McDermott name was Conor McDermott, who was the last chief of the clan in the 16th century. He fought against the English forces during the Nine Years' War (1594-1603) and was eventually forced to surrender his lands in the early 17th century as part of the Plantation of Ulster.
Other notable individuals with the McDermott surname include:
1. Brian McDermott (1949-), an English former professional footballer and manager.
2. John McDermott (1891-1957), an American baseball player and manager.
3. Seán McDermott (1904-1966), an Irish republican and member of the Irish Republican Army (IRA).
4. Terry McDermott (1951-), an English former professional footballer and manager.
5. William McDermott (1832-1886), an Irish-American inventor and entrepreneur who co-founded the McDermott Shipyard in New Jersey.
While the McDermott name has evolved over the centuries, its roots can be traced back to the ancient Gaelic culture of Ireland and the McDermott clan's historical prominence in the region of Connacht.
Demographics
Ancestry and ethnicity for Mcdermott
Among Census respondents with the surname Mcdermott, the largest self-reported group is White at 89.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (3.2%).
The bar chart below shows how Mcdermott 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 Mcdermott surname at the time of the 2020 Census, not any inherent property of the name itself.
- White89.2% · 26,597
- Hispanic or Latino3.7% · 1,113
- Two or more races3.2% · 953
- Black or African American2.6% · 788
- Asian and Pacific Islander1.0% · 302
- American Indian and Alaska Native0.2% · 54
Timeline
Historical Census data for Mcdermott
Mcdermott 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
#1,151
National surname rank
Recorded bearers 30,528
+1,088 bearers (+3.7%)
Per 100,000 10.35
Rank movement Down 65 places
2020
#1,157
National surname rank
Recorded bearers 29,807
-721 bearers (-2.4%)
Per 100,000 9.97
Rank movement Down 6 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #1,086 | 29,440 | 10.91 | First available Census row | First available Census row |
| 2010 | #1,151 | 30,528 | 10.35 | +1,088 bearers (+3.7%) | Down 65 places |
| 2020 | #1,157 | 29,807 | 9.97 | -721 bearers (-2.4%) | Down 6 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 Mcdermott 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 | #1,151 | #1,157 | -0.5% |
| Count | 30,528 | 29,807 | -2.4% |
| Per 100K | 10.35 | 9.97 | -3.6% |
Between the 2010 and 2020 Census, the number of Mcdermott bearers went from 30,528 to 29,807 (-2.4% change). The surname moved down 6 positions in the national ranking, going from #1,151 to #1,157.
Notable bearers
Famous people with the surname Mcdermott
FAQ
Mcdermott surname: questions and answers
How many people in the U.S. have the surname Mcdermott?
Name Census estimates that about 34,180 living Americans carry the surname Mcdermott. Using the current population baseline, that works out to roughly 1 in 10,028 residents.
How common is Mcdermott?
Mcdermott ranks #1,157 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 9.97 per 100,000 residents, which is about 10 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 29,807 people with the surname Mcdermott. That is different from the site's living-bearer estimate (34,180), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 9.97 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 9.97 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 10 of them to have the surname Mcdermott.
Has Mcdermott become more or less common over time?
Between 2010 and 2020, the surname Mcdermott went from 30,528 recorded bearers to 29,807. That is a decrease of 721 (-2.4%). In the national ranking it fell from #1,151 to #1,157.
What does the Census say about the background of Mcdermott?
Among Census respondents with the surname Mcdermott, the largest self-reported group is White at 89.2%. The next largest groups are Hispanic (3.7%) and Two or More Races (3.2%). 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 Mcdermott in the 2020 Census, accounting for 89.2% (26,597 people in the source table).
What is the full ancestry breakdown?
Mcdermott appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (89.2%), Hispanic (3.7%), Two or More Races (3.2%). 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 Mcdermott (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 Mcdermott mean?
Derived from the Gaelic "Mac Diarmada," meaning "son of Diarmaid," a popular Irish personal name meaning "free from envy." 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 Mcdermott (9.97 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 Mcdermott?
See how many Americans have the surname Mcdermott on HowManyOfMe.org, our sister site built around that single question.