2000
#142,819
National surname rank
Recorded bearers 107
First available Census row
Per 100,000 0.04
Very Rare Last name
Decareau
Derived from French de carre, meaning "from the square or village", implying a place name origin.
According to the 2020 US Census Bureau surname tables, roughly 125 Americans carry the last name Decareau. That puts it at #150,205 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,742,035 residents).
This page is the full Name Census profile for the Decareau 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
125
1 in 2,742,035
Census rank
#150,205
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
109
very rare in the US
Popularity narrative
The Census Bureau recorded 109 bearers of the surname Decareau in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 150205th position in the national surname ranking.
Among Census respondents with the surname Decareau, the largest self-reported group is White at 87.2%. The next largest groups are Black (5.5%) and Two or More Races (3.7%).
Origin
Meaning and origin of Decareau
The surname DECAREAU is of French origin, originating in the northern regions of France during the medieval period. It is derived from the Old French words "de" meaning "from" and "careau" meaning "square" or "quadrangle." This suggests that the name may have been given to someone who lived near a square or a quadrangle-shaped area.
One of the earliest recorded instances of the name DECAREAU can be found in the "Livre Terrier de Mouchy-le-Châtel," a census-like document from the 13th century. This document mentions a "Jehan Decareau" as a landowner in the village of Mouchy-le-Châtel, located in the Picardy region of northern France.
In the 16th century, the name DECAREAU appeared in the records of the city of Amiens, also in the Picardy region. A "Nicolas Decareau" was listed as a merchant and guild member in the year 1572.
During the 17th century, the DECAREAU family began to spread across France. In 1634, a "Pierre Decareau" was recorded as a farmer in the village of Beaumont-sur-Oise, near Paris. This may be an indication of the family's migration from northern France towards the capital region.
One notable individual bearing the surname DECAREAU was Jacques Decareau, a French playwright and poet born in 1680 in Rouen, Normandy. He is known for his satirical works critiquing the social and political climate of his time.
In the 18th century, the DECAREAU name appeared in the records of the city of Bordeaux, suggesting that the family had also established roots in southwestern France. A "Marie Decareau" was listed as a merchant's wife in the city's census of 1765.
Another significant figure with the DECAREAU surname was Jean-Baptiste Decareau, a French military officer born in 1745 in Montpellier. He served in the French Revolutionary Wars and rose to the rank of brigadier general before his death in 1805.
Throughout the 19th century, the DECAREAU name continued to be present in various regions of France. However, the surname appears to have been most concentrated in the northern parts of the country, particularly in the regions of Picardy, Normandy, and Île-de-France.
Demographics
Ancestry and ethnicity for Decareau
Among Census respondents with the surname Decareau, the largest self-reported group is White at 87.2%. The next largest groups are Black (5.5%) and Two or More Races (3.7%).
The bar chart below shows how Decareau 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 Decareau surname at the time of the 2020 Census, not any inherent property of the name itself.
- White87.2% · 95
- Black or African American5.5% · 6
- Two or more races3.7% · 4
- Asian and Pacific Islander2.8% · 3
- Hispanic or Latino0.9% · 1
Timeline
Historical Census data for Decareau
Decareau 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
#126,018
National surname rank
Recorded bearers 136
+29 bearers (+27.1%)
Per 100,000 0.05
Rank movement Up 16,801 places
2020
#150,205
National surname rank
Recorded bearers 109
-27 bearers (-19.9%)
Per 100,000 0.04
Rank movement Down 24,187 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #142,819 | 107 | 0.04 | First available Census row | First available Census row |
| 2010 | #126,018 | 136 | 0.05 | +29 bearers (+27.1%) | Up 16,801 places |
| 2020 | #150,205 | 109 | 0.04 | -27 bearers (-19.9%) | Down 24,187 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 Decareau 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 | #126,018 | #150,205 | -19.2% |
| Count | 136 | 109 | -19.9% |
| Per 100K | 0.05 | 0.04 | -27.1% |
Between the 2010 and 2020 Census, the number of Decareau bearers went from 136 to 109 (-19.9% change). The surname moved down 24,187 positions in the national ranking, going from #126,018 to #150,205.
FAQ
Decareau surname: questions and answers
How many people in the U.S. have the surname Decareau?
Name Census estimates that about 125 living Americans carry the surname Decareau. Using the current population baseline, that works out to roughly 1 in 2,742,035 residents.
How common is Decareau?
Decareau ranks #150,205 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 109 people with the surname Decareau. That is different from the site's living-bearer estimate (125), 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 Decareau.
Has Decareau become more or less common over time?
Between 2010 and 2020, the surname Decareau went from 136 recorded bearers to 109. That is a decrease of 27 (-19.9%). In the national ranking it fell from #126,018 to #150,205.
What does the Census say about the background of Decareau?
Among Census respondents with the surname Decareau, the largest self-reported group is White at 87.2%. The next largest groups are Black (5.5%) and Two or More Races (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 Decareau in the 2020 Census, accounting for 87.2% (95 people in the source table).
What is the full ancestry breakdown?
Decareau appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (87.2%), Black (5.5%), Two or More Races (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 Decareau (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 Decareau mean?
Derived from French de carre, meaning "from the square or village", implying a place name origin. 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 Decareau (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 surname Decareau?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.