2000
#37,881
National surname rank
Recorded bearers 551
First available Census row
Per 100,000 0.20
Rare Last name
Un
A surname of Chinese origin meaning "cloud" or "cloudy".
According to the 2020 US Census Bureau surname tables, roughly 1,136 Americans carry the last name Un. That puts it at #25,996 in the national surname ranking, appearing at a frequency of 0.33 per 100,000 people (about 1 in 301,720 residents).
This page is the full Name Census profile for the Un 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
1.1K
1 in 301,720
Census rank
#25,996
2020 decennial data
Per 100,000
0.3
Frequency rate
Recorded bearers
991
rare in the US
Popularity narrative
The Census Bureau recorded 991 bearers of the surname Un in its 2020 decennial surname file. At a rate of 0.33 per 100,000 residents, it holds the 25996th position in the national surname ranking.
Among Census respondents with the surname Un, the largest self-reported group is Asian/Pacific Islander at 72.4%. The next largest groups are White (14.4%) and Hispanic (5.5%).
Origin
Meaning and origin of Un
The surname "UN" is believed to have originated in the region of Normandy in northern France during the early Middle Ages. It is derived from the Old French word "un," meaning "one" or "a single." This suggests that the name may have been initially given as a descriptive nickname or to distinguish an individual from others with the same given name.
One of the earliest recorded instances of the surname "UN" can be found in the Doomsday Book, a comprehensive survey commissioned by William the Conqueror in 1086. The name appears in various spellings, such as "Un," "Unu," and "Vun," reflecting the linguistic variations of the time.
During the 12th century, the surname "UN" was associated with several prominent figures in Normandy. One notable example is Raoul Un, a wealthy landowner and nobleman who played a significant role in the construction of the Abbey of Fécamp in the late 1100s.
In the 13th century, the name "UN" appeared in various records across Normandy and neighboring regions. Jacques Un, a merchant from Rouen, was documented as a member of the city's influential guild system in 1245. Additionally, Marguerite Un, a noblewoman from Caen, was recorded as a benefactor of the local cathedral in 1268.
As the surname spread across Europe, it took on various regional variations. In England, for instance, the name was often spelled as "Onne" or "Onn," as evidenced by records from the 14th and 15th centuries. One notable bearer was Sir William Onne, a knight who fought alongside King Henry V at the Battle of Agincourt in 1415.
In the 16th century, the "UN" surname gained prominence in the Low Countries (modern-day Belgium and the Netherlands). Pieter Un, a renowned painter from Antwerp, was celebrated for his religious artworks and portraits during this period (1520-1598).
Throughout the centuries, the surname "UN" has been associated with various notable individuals across different fields. For example, Étienne Un (1633-1707) was a prominent French mathematician and astronomer, while Johan Un (1780-1845) was a respected Dutch philosopher and scholar.
Demographics
Ancestry and ethnicity for Un
Among Census respondents with the surname Un, the largest self-reported group is Asian/Pacific Islander at 72.4%. The next largest groups are White (14.4%) and Hispanic (5.5%).
The bar chart below shows how Un 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 Un surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander72.4% · 717
- White14.4% · 143
- Hispanic or Latino5.5% · 55
- Two or more races4.1% · 41
- Black or African American3.2% · 32
- American Indian and Alaska Native0.3% · 3
Timeline
Historical Census data for Un
Un 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
#31,873
National surname rank
Recorded bearers 724
+173 bearers (+31.4%)
Per 100,000 0.25
Rank movement Up 6,008 places
2020
#25,996
National surname rank
Recorded bearers 991
+267 bearers (+36.9%)
Per 100,000 0.33
Rank movement Up 5,877 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #37,881 | 551 | 0.20 | First available Census row | First available Census row |
| 2010 | #31,873 | 724 | 0.25 | +173 bearers (+31.4%) | Up 6,008 places |
| 2020 | #25,996 | 991 | 0.33 | +267 bearers (+36.9%) | Up 5,877 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 Un 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 | #31,873 | #25,996 | 18.4% |
| Count | 724 | 991 | 36.9% |
| Per 100K | 0.25 | 0.33 | 32.6% |
Between the 2010 and 2020 Census, the number of Un bearers went from 724 to 991 (+36.9% change). The surname moved up 5,877 positions in the national ranking, going from #31,873 to #25,996.
FAQ
Un surname: questions and answers
How many people in the U.S. have the surname Un?
Name Census estimates that about 1,136 living Americans carry the surname Un. Using the current population baseline, that works out to roughly 1 in 301,720 residents.
How common is Un?
Un ranks #25,996 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.33 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 991 people with the surname Un. That is different from the site's living-bearer estimate (1,136), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.33 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.33 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 Un.
Has Un become more or less common over time?
Between 2010 and 2020, the surname Un went from 724 recorded bearers to 991. That is an increase of 267 (+36.9%). In the national ranking it rose from #31,873 to #25,996.
What does the Census say about the background of Un?
Among Census respondents with the surname Un, the largest self-reported group is Asian/Pacific Islander at 72.4%. The next largest groups are White (14.4%) and Hispanic (5.5%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Un in the 2020 Census, accounting for 72.4% (717 people in the source table).
What is the full ancestry breakdown?
Un appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (72.4%), White (14.4%), Hispanic (5.5%). 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 Un (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 Un mean?
A surname of Chinese origin meaning "cloud" or "cloudy". 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 Un (0.33 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 common is the surname Un?
See how many people have the surname Un on HowManyOfMe.org, our sister site built around that single question.