2000
#1,215
National surname rank
Recorded bearers 26,403
First available Census row
Per 100,000 9.79
Uncommon Last name
Dempsey
An Irish surname derived from the Gaelic Ó Díomasaigh, meaning "descendant of Díomasach," a personal name meaning "proud."
According to the 2020 US Census Bureau surname tables, roughly 29,700 Americans carry the last name Dempsey. That puts it at #1,330 in the national surname ranking, appearing at a frequency of 8.67 per 100,000 people (about 1 in 11,541 residents).
This page is the full Name Census profile for the Dempsey 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 Dempsey with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
30K
1 in 11,541
Census rank
#1,330
2020 decennial data
Per 100,000
8.7
Frequency rate
Recorded bearers
26K
uncommon in the US
Popularity narrative
The Census Bureau recorded 25,900 bearers of the surname Dempsey in its 2020 decennial surname file. At a rate of 8.67 per 100,000 residents, it holds the 1330th position in the national surname ranking.
Among Census respondents with the surname Dempsey, the largest self-reported group is White at 85.7%. The next largest groups are Black (5.5%) and Hispanic (3.7%).
Origin
Meaning and origin of Dempsey
The surname Dempsey has its origins in Ireland, where it first emerged in the early medieval period. It is derived from the Gaelic Ó Díomasaigh, which means "descendant of Díomasach." The name Díomasach itself comes from the word "diomus," meaning "proud" or "arrogant."
One of the earliest recorded instances of the name Dempsey can be found in the Annals of the Four Masters, a chronicle of medieval Irish history. In the year 1172, the annals mention a Diarmaid Ó Diomusaigh, who was a chief of the Uí Ceinnsealaigh, a powerful family in the medieval Irish kingdom of Leinster.
During the Norman invasion of Ireland in the 12th century, the name Dempsey became more widespread as members of the family were dispersed across the island. In the 14th century, the name appeared in various records, including the Pipe Rolls of Cloyne, which listed a William Dempsey in County Cork in 1367.
Over the centuries, the name Dempsey has been associated with several prominent figures in Irish history. One notable example is Jeremiah Dempsey (c. 1589-1667), who was a Roman Catholic priest and a prominent member of the Confederate Catholic Association during the Irish Confederate Wars of the 1640s.
Another notable Dempsey was Patrick Dempsey (1858-1915), an Irish-born American businessman and philanthropist who co-founded the Dempsey Brewing Company in Waterloo, Iowa. He was also involved in various civic and charitable organizations in the area.
In the realm of sports, Jack Dempsey (1895-1983) was a famous American boxer who held the world heavyweight championship from 1919 to 1926. He was born William Harrison Dempsey and was of Irish descent.
The name Dempsey has also been associated with various place names in Ireland, such as Dempsey's Head in County Waterford and Dempsey's Rock in County Wexford, both of which are named after local landowners or families bearing the Dempsey surname.
Throughout its long history, the surname Dempsey has maintained a strong connection to its Irish roots, with many families tracing their lineage back to the medieval Uí Ceinnsealaigh dynasty and the original Gaelic form of the name, Ó Díomasaigh.
Demographics
Ancestry and ethnicity for Dempsey
Among Census respondents with the surname Dempsey, the largest self-reported group is White at 85.7%. The next largest groups are Black (5.5%) and Hispanic (3.7%).
The bar chart below shows how Dempsey 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 Dempsey surname at the time of the 2020 Census, not any inherent property of the name itself.
- White85.7% · 22,206
- Black or African American5.5% · 1,421
- Hispanic or Latino3.7% · 949
- Two or more races3.6% · 945
- American Indian and Alaska Native0.7% · 191
- Asian and Pacific Islander0.7% · 188
Timeline
Historical Census data for Dempsey
Dempsey 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
#1,308
National surname rank
Recorded bearers 26,863
+460 bearers (+1.7%)
Per 100,000 9.11
Rank movement Down 93 places
2020
#1,330
National surname rank
Recorded bearers 25,900
-963 bearers (-3.6%)
Per 100,000 8.67
Rank movement Down 22 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #1,215 | 26,403 | 9.79 | First available Census row | First available Census row |
| 2010 | #1,308 | 26,863 | 9.11 | +460 bearers (+1.7%) | Down 93 places |
| 2020 | #1,330 | 25,900 | 8.67 | -963 bearers (-3.6%) | Down 22 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 Dempsey 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 | #1,308 | #1,330 | -1.7% |
| Count | 26,863 | 25,900 | -3.6% |
| Per 100K | 9.11 | 8.67 | -4.9% |
Between the 2010 and 2020 Census, the number of Dempsey bearers went from 26,863 to 25,900 (-3.6% change). The surname moved down 22 positions in the national ranking, going from #1,308 to #1,330.
Notable bearers
Famous people with the surname Dempsey
FAQ
Dempsey surname: questions and answers
How many people in the U.S. have the surname Dempsey?
Name Census estimates that about 29,700 living Americans carry the surname Dempsey. Using the current population baseline, that works out to roughly 1 in 11,541 residents.
How common is Dempsey?
Dempsey ranks #1,330 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 8.67 per 100,000 residents, which is about 9 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 25,900 people with the surname Dempsey. That is different from the site's living-bearer estimate (29,700), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 8.67 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 8.67 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 9 of them to have the surname Dempsey.
Has Dempsey become more or less common over time?
Between 2010 and 2020, the surname Dempsey went from 26,863 recorded bearers to 25,900. That is a decrease of 963 (-3.6%). In the national ranking it fell from #1,308 to #1,330.
What does the Census say about the background of Dempsey?
Among Census respondents with the surname Dempsey, the largest self-reported group is White at 85.7%. The next largest groups are Black (5.5%) and Hispanic (3.7%). 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 Dempsey in the 2020 Census, accounting for 85.7% (22,206 people in the source table).
What is the full ancestry breakdown?
Dempsey appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (85.7%), Black (5.5%), Hispanic (3.7%). 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 Dempsey (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 Dempsey mean?
An Irish surname derived from the Gaelic Ó Díomasaigh, meaning "descendant of Díomasach," a personal name meaning "proud." 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 Dempsey (8.67 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 Dempsey?
If you just want to know how many people have the last name Dempsey, HowManyOfMe.org gives you the headline number in one glance.