2000
#116,835
National surname rank
Recorded bearers 138
First available Census row
Per 100,000 0.05
Very Rare Last name
Koosman
A Dutch surname derived from the personal name "Koos", a nickname form of Jacob.
According to the 2020 US Census Bureau surname tables, roughly 151 Americans carry the last name Koosman. That puts it at #133,220 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,269,896 residents).
This page is the full Name Census profile for the Koosman 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
151
1 in 2,269,896
Census rank
#133,220
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
132
very rare in the US
Popularity narrative
The Census Bureau recorded 132 bearers of the surname Koosman in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 133220th position in the national surname ranking.
Among Census respondents with the surname Koosman, the largest self-reported group is White at 93.2%. The next largest groups are American Indian/Alaska Native (2.3%) and Hispanic (1.5%).
Origin
Meaning and origin of Koosman
The surname KOOSMAN has its origins in the Netherlands, specifically in the northern region of Friesland. Originating in the late 16th century, it is believed to be derived from the Dutch word "koos," which means "cool" or "chilly," and the suffix "-man," referring to a person or individual. This suggests that the name may have been initially bestowed upon someone who had a cool or calm demeanor.
One of the earliest recorded instances of the KOOSMAN name dates back to the Dutch village of Wolvega in the year 1587, where it appears in a local parish register. It is also found in historical documents from the nearby towns of Heerenveen and Dokkum during the 17th century.
A notable figure bearing the KOOSMAN name was Pieter Koosman, a Dutch merchant and ship owner who lived in the city of Haarlem from 1621 to 1692. Records indicate that he played a significant role in the maritime trade between the Netherlands and various European ports.
In the 18th century, the name KOOSMAN appears in the municipal archives of Amsterdam, where it is associated with a family of prosperous brewers. One member of this family, Jan Koosman (1734-1795), is recorded as having served as a city councilor in Amsterdam during the latter part of his life.
As the Dutch began to establish colonies in the Americas and other parts of the world, the KOOSMAN name also spread to these regions. In the 19th century, a prominent figure named Dirk Koosman (1812-1887) was a successful farmer and landowner in the Dutch Cape Colony, which is now part of South Africa.
Another individual of note was Johanna Koosman (1841-1923), a Dutch-American author and journalist who wrote extensively about the experiences of Dutch immigrants in the United States. She was born in the Netherlands but later settled in New York City, where she became a influential voice in the local Dutch community.
Throughout its history, the KOOSMAN surname has maintained a strong presence in the Netherlands and among Dutch diaspora communities around the world. While not a particularly common name, it has been borne by individuals across various professions and walks of life, from merchants and farmers to writers and public servants.
Demographics
Ancestry and ethnicity for Koosman
Among Census respondents with the surname Koosman, the largest self-reported group is White at 93.2%. The next largest groups are American Indian/Alaska Native (2.3%) and Hispanic (1.5%).
The bar chart below shows how Koosman 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 Koosman surname at the time of the 2020 Census, not any inherent property of the name itself.
- White93.2% · 123
- American Indian and Alaska Native2.3% · 3
- Hispanic or Latino1.5% · 2
- Two or more races1.5% · 2
- Black or African American0.8% · 1
- Asian and Pacific Islander0.8% · 1
Timeline
Historical Census data for Koosman
Koosman 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
#127,494
National surname rank
Recorded bearers 134
-4 bearers (-2.9%)
Per 100,000 0.05
Rank movement Down 10,659 places
2020
#133,220
National surname rank
Recorded bearers 132
-2 bearers (-1.5%)
Per 100,000 0.04
Rank movement Down 5,726 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #116,835 | 138 | 0.05 | First available Census row | First available Census row |
| 2010 | #127,494 | 134 | 0.05 | -4 bearers (-2.9%) | Down 10,659 places |
| 2020 | #133,220 | 132 | 0.04 | -2 bearers (-1.5%) | Down 5,726 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 Koosman 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 | #127,494 | #133,220 | -4.5% |
| Count | 134 | 132 | -1.5% |
| Per 100K | 0.05 | 0.04 | -11.7% |
Between the 2010 and 2020 Census, the number of Koosman bearers went from 134 to 132 (-1.5% change). The surname moved down 5,726 positions in the national ranking, going from #127,494 to #133,220.
Notable bearers
Famous people with the surname Koosman
FAQ
Koosman surname: questions and answers
How many people in the U.S. have the surname Koosman?
Name Census estimates that about 151 living Americans carry the surname Koosman. Using the current population baseline, that works out to roughly 1 in 2,269,896 residents.
How common is Koosman?
Koosman ranks #133,220 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 132 people with the surname Koosman. That is different from the site's living-bearer estimate (151), 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 Koosman.
Has Koosman become more or less common over time?
Between 2010 and 2020, the surname Koosman went from 134 recorded bearers to 132. That is a decrease of 2 (-1.5%). In the national ranking it fell from #127,494 to #133,220.
What does the Census say about the background of Koosman?
Among Census respondents with the surname Koosman, the largest self-reported group is White at 93.2%. The next largest groups are American Indian/Alaska Native (2.3%) and Hispanic (1.5%). 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?
White is the largest self-reported group for the surname Koosman in the 2020 Census, accounting for 93.2% (123 people in the source table).
What is the full ancestry breakdown?
Koosman appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (93.2%), American Indian/Alaska Native (2.3%), Hispanic (1.5%). 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 Koosman (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 Koosman mean?
A Dutch surname derived from the personal name "Koos", a nickname form of Jacob. 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 Koosman (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 Koosman?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.