2000
#5,195
National surname rank
Recorded bearers 6,177
First available Census row
Per 100,000 2.29
Rare Last name
Au
A Chinese surname meaning "profound" or "to meet," or a Vietnamese surname referring to the Âu Việt people.
According to the 2020 US Census Bureau surname tables, roughly 8,568 Americans carry the last name Au. That puts it at #4,606 in the national surname ranking, appearing at a frequency of 2.50 per 100,000 people (about 1 in 40,004 residents).
This page is the full Name Census profile for the Au 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 Au with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
8.6K
1 in 40,004
Census rank
#4,606
2020 decennial data
Per 100,000
2.5
Frequency rate
Recorded bearers
7.5K
rare in the US
Popularity narrative
The Census Bureau recorded 7,472 bearers of the surname Au in its 2020 decennial surname file. At a rate of 2.50 per 100,000 residents, it holds the 4606th position in the national surname ranking.
Among Census respondents with the surname Au, the largest self-reported group is Asian/Pacific Islander at 83.9%. The next largest groups are White (7.6%) and Two or More Races (5.2%).
Origin
Meaning and origin of Au
The surname "Au" originates from the French region of Normandy in the early 11th century. It is derived from the Old French word "au", meaning "to the" or "at the", which was often used as a prefix in place names. This suggests that the name may have originally referred to someone who lived near a specific landmark or location.
One of the earliest recorded instances of the name "Au" can be found in the Domesday Book of 1086, a survey commissioned by William the Conqueror to record landholders and properties throughout England. This suggests that individuals bearing this surname may have been among the Norman settlers who arrived in England following the Norman Conquest of 1066.
During the Middle Ages, the name "Au" appeared in various spellings, including "Atte Au", "Atte Awe", and "De Awe", reflecting the linguistic changes and variations common in that era. These variations often indicated the person's place of origin or residence.
Notable individuals with the surname "Au" throughout history include:
1. Jean d'Au (c. 1350-1420), a French nobleman and military commander who fought in the Hundred Years' War.
2. Robert Au (1495-1568), an English merchant and Member of Parliament during the reign of Queen Elizabeth I.
3. Marie-Thérèse Au (1680-1755), a French poet and author renowned for her works on religious themes.
4. Louis-André Au (1731-1802), a French architect and urban planner who contributed to the redesign of several cities in France and Belgium.
5. Elizabeth Au (1819-1891), an American social reformer and abolitionist who worked alongside notable figures like Frederick Douglass and William Lloyd Garrison.
As the surname "Au" spread across Europe and beyond, it likely acquired additional meanings and associations based on local customs and interpretations. However, its roots can be traced back to the Norman settlers who brought this name to England in the 11th century.
Demographics
Ancestry and ethnicity for Au
Among Census respondents with the surname Au, the largest self-reported group is Asian/Pacific Islander at 83.9%. The next largest groups are White (7.6%) and Two or More Races (5.2%).
The bar chart below shows how Au 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 Au surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander83.9% · 6,269
- White7.6% · 566
- Two or more races5.2% · 386
- Hispanic or Latino2.8% · 212
- Black or African American0.5% · 35
- American Indian and Alaska Native0.1% · 4
Timeline
Historical Census data for Au
Au 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
#4,919
National surname rank
Recorded bearers 7,148
+971 bearers (+15.7%)
Per 100,000 2.42
Rank movement Up 276 places
2020
#4,606
National surname rank
Recorded bearers 7,472
+324 bearers (+4.5%)
Per 100,000 2.50
Rank movement Up 313 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #5,195 | 6,177 | 2.29 | First available Census row | First available Census row |
| 2010 | #4,919 | 7,148 | 2.42 | +971 bearers (+15.7%) | Up 276 places |
| 2020 | #4,606 | 7,472 | 2.50 | +324 bearers (+4.5%) | Up 313 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 Au 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 | #4,919 | #4,606 | 6.4% |
| Count | 7,148 | 7,472 | 4.5% |
| Per 100K | 2.42 | 2.50 | 3.3% |
Between the 2010 and 2020 Census, the number of Au bearers went from 7,148 to 7,472 (+4.5% change). The surname moved up 313 positions in the national ranking, going from #4,919 to #4,606.
FAQ
Au surname: questions and answers
How many people in the U.S. have the surname Au?
Name Census estimates that about 8,568 living Americans carry the surname Au. Using the current population baseline, that works out to roughly 1 in 40,004 residents.
How common is Au?
Au ranks #4,606 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 2.50 per 100,000 residents, which is about 2 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 7,472 people with the surname Au. That is different from the site's living-bearer estimate (8,568), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 2.5 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 2.50 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 2 of them to have the surname Au.
Has Au become more or less common over time?
Between 2010 and 2020, the surname Au went from 7,148 recorded bearers to 7,472. That is an increase of 324 (+4.5%). In the national ranking it rose from #4,919 to #4,606.
What does the Census say about the background of Au?
Among Census respondents with the surname Au, the largest self-reported group is Asian/Pacific Islander at 83.9%. The next largest groups are White (7.6%) and Two or More Races (5.2%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Au in the 2020 Census, accounting for 83.9% (6,269 people in the source table).
What is the full ancestry breakdown?
Au appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (83.9%), White (7.6%), Two or More Races (5.2%). 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 Au (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 Au mean?
A Chinese surname meaning "profound" or "to meet," or a Vietnamese surname referring to the Âu Việt people. 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 Au (2.50 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 Au?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.