2000
#119,644
National surname rank
Recorded bearers 134
First available Census row
Per 100,000 0.05
Very Rare Last name
Casterlow
A locational surname indicating someone from a place called Casterlow.
According to the 2020 US Census Bureau surname tables, roughly 119 Americans carry the last name Casterlow. That puts it at #153,590 in the national surname ranking, appearing at a frequency of 0.03 per 100,000 people (about 1 in 2,880,289 residents).
This page is the full Name Census profile for the Casterlow 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
119
1 in 2,880,289
Census rank
#153,590
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
104
very rare in the US
Popularity narrative
The Census Bureau recorded 104 bearers of the surname Casterlow in its 2020 decennial surname file. At a rate of 0.03 per 100,000 residents, it holds the 153590th position in the national surname ranking.
Among Census respondents with the surname Casterlow, the largest self-reported group is Black at 94.2%. The next largest groups are Two or More Races (2.9%) and Hispanic (1.9%).
Origin
Meaning and origin of Casterlow
The surname Casterlow originated in the English county of Lancashire during the late medieval period. It is derived from the Old English words "cæster" meaning a fortified town or city, and "hlaw" meaning a small hill or mound. This suggests the name likely referred to someone who lived near a fortified settlement built on a hill or raised ground.
Some of the earliest recorded spellings of the name include Castrelowe in the Subsidy Rolls of Lancashire in 1332, and Casterlo in the Pipe Rolls of Yorkshire in 1379. These variations highlight how surnames evolved through different pronunciations and spellings over time. The name may also be related to place names like Casterton in Westmorland, which was recorded in the Domesday Book of 1086 as "Castretune."
One of the earliest known bearers of the Casterlow surname was Richard de Casterlow, who was mentioned in the Court Rolls of Lancashire in 1412. Another early record is Thomas Casterlow, whose son John was baptized in the parish of Barton-upon-Irwell, Lancashire in 1509.
During the 16th century, the Casterlow family was well-established in the area around Manchester, with members recorded in local parish registers. Notable individuals include Edward Casterlow (1565-1633), a wealthy landowner and alderman of Manchester, and his son John Casterlow (1598-1672), who served as a captain in the Parliamentarian forces during the English Civil War.
Other prominent bearers of the name include Reverend William Casterlow (1701-1778), a Church of England clergyman who served as Rector of St. Mary's in Bury, Lancashire for over 40 years. In the 19th century, James Casterlow (1823-1897) was a successful cotton manufacturer and philanthropist in Oldham, while his cousin Henry Casterlow (1830-1914) was a renowned architect who designed many churches and public buildings across northern England.
Demographics
Ancestry and ethnicity for Casterlow
Among Census respondents with the surname Casterlow, the largest self-reported group is Black at 94.2%. The next largest groups are Two or More Races (2.9%) and Hispanic (1.9%).
The bar chart below shows how Casterlow 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 Casterlow surname at the time of the 2020 Census, not any inherent property of the name itself.
- Black or African American94.2% · 98
- Two or more races2.9% · 3
- Hispanic or Latino1.9% · 2
- White1.0% · 1
Timeline
Historical Census data for Casterlow
Casterlow 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
#138,304
National surname rank
Recorded bearers 121
-13 bearers (-9.7%)
Per 100,000 0.04
Rank movement Down 18,660 places
2020
#153,590
National surname rank
Recorded bearers 104
-17 bearers (-14.0%)
Per 100,000 0.03
Rank movement Down 15,286 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #119,644 | 134 | 0.05 | First available Census row | First available Census row |
| 2010 | #138,304 | 121 | 0.04 | -13 bearers (-9.7%) | Down 18,660 places |
| 2020 | #153,590 | 104 | 0.03 | -17 bearers (-14.0%) | Down 15,286 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 Casterlow 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 | #138,304 | #153,590 | -11.1% |
| Count | 121 | 104 | -14.0% |
| Per 100K | 0.04 | 0.03 | -13.0% |
Between the 2010 and 2020 Census, the number of Casterlow bearers went from 121 to 104 (-14.0% change). The surname moved down 15,286 positions in the national ranking, going from #138,304 to #153,590.
FAQ
Casterlow surname: questions and answers
How many people in the U.S. have the surname Casterlow?
Name Census estimates that about 119 living Americans carry the surname Casterlow. Using the current population baseline, that works out to roughly 1 in 2,880,289 residents.
How common is Casterlow?
Casterlow ranks #153,590 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.03 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 104 people with the surname Casterlow. That is different from the site's living-bearer estimate (119), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.03 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.03 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 Casterlow.
Has Casterlow become more or less common over time?
Between 2010 and 2020, the surname Casterlow went from 121 recorded bearers to 104. That is a decrease of 17 (-14.0%). In the national ranking it fell from #138,304 to #153,590.
What does the Census say about the background of Casterlow?
Among Census respondents with the surname Casterlow, the largest self-reported group is Black at 94.2%. The next largest groups are Two or More Races (2.9%) and Hispanic (1.9%). 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?
Black is the largest self-reported group for the surname Casterlow in the 2020 Census, accounting for 94.2% (98 people in the source table).
What is the full ancestry breakdown?
Casterlow appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Black (94.2%), Two or More Races (2.9%), Hispanic (1.9%). 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 Casterlow (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 Casterlow mean?
A locational surname indicating someone from a place called Casterlow. 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 Casterlow (0.03 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 Casterlow?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.