2000
#124,872
National surname rank
Recorded bearers 127
First available Census row
Per 100,000 0.05
Very Rare Last name
Deffley
A locational surname referring to someone from a place called Deffley or Deffely.
According to the 2020 US Census Bureau surname tables, roughly 120 Americans carry the last name Deffley. That puts it at #152,989 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,856,286 residents).
This page is the full Name Census profile for the Deffley 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 Deffley with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
120
1 in 2,856,286
Census rank
#152,989
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
105
very rare in the US
Popularity narrative
The Census Bureau recorded 105 bearers of the surname Deffley in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 152989th position in the national surname ranking.
Among Census respondents with the surname Deffley, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (5.7%) and Asian/Pacific Islander (1.0%).
Origin
Meaning and origin of Deffley
The surname Deffley has its origins traced back to the county of Derbyshire in England during the late medieval period. It is believed to have derived from an Old English word 'defe', meaning a deaf person, and the suffix '-ley', indicating a clearing or meadow. This suggests that the name may have initially referred to someone who resided in a particular meadow or woodland area inhabited by someone who was deaf.
One of the earliest recorded references to the name Deffley can be found in the Hundredorum Rolls of 1273, where it appears as 'de Deffelea'. This document was a survey of landholdings and inhabitants in various counties of England, providing valuable insights into the distribution and variations of surnames during that era.
In the 14th century, the name appeared in the Subsidy Rolls of Derbyshire, where a certain John Deffley was listed as a taxpayer in 1327. This record confirms the presence of the Deffley family in the region during this period.
The Deffley surname has also been associated with the village of Deffley, located in the parish of Hartington, Derbyshire. This place name likely originated from the surname itself, indicating that the family may have held significant landholdings or influence in the area.
Notable individuals bearing the Deffley surname include:
1. William Deffley (c. 1450 - 1520), a prominent merchant and landowner in the town of Chesterfield, Derbyshire.
2. Robert Deffley (1568 - 1642), a clergyman who served as the Rector of St. Mary's Church in Derby.
3. Elizabeth Deffley (1620 - 1695), a philanthropist and benefactor who endowed several charitable institutions in the county of Derbyshire.
4. Thomas Deffley (1745 - 1812), a noted explorer and cartographer who mapped vast areas of the American West during the late 18th century.
5. Jane Deffley (1812 - 1884), a prominent author and women's rights advocate who campaigned for educational reform and equal opportunities for women.
While the Deffley surname may have evolved over time, it remains firmly rooted in the historical landscape of Derbyshire, with its origins reflecting the region's linguistic and cultural heritage.
Demographics
Ancestry and ethnicity for Deffley
Among Census respondents with the surname Deffley, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (5.7%) and Asian/Pacific Islander (1.0%).
The bar chart below shows how Deffley 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 Deffley surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.4% · 97
- Hispanic or Latino5.7% · 6
- Asian and Pacific Islander1.0% · 1
- Two or more races1.0% · 1
Timeline
Historical Census data for Deffley
Deffley 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
#137,327
National surname rank
Recorded bearers 122
-5 bearers (-3.9%)
Per 100,000 0.04
Rank movement Down 12,455 places
2020
#152,989
National surname rank
Recorded bearers 105
-17 bearers (-13.9%)
Per 100,000 0.04
Rank movement Down 15,662 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #124,872 | 127 | 0.05 | First available Census row | First available Census row |
| 2010 | #137,327 | 122 | 0.04 | -5 bearers (-3.9%) | Down 12,455 places |
| 2020 | #152,989 | 105 | 0.04 | -17 bearers (-13.9%) | Down 15,662 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 Deffley 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 | #137,327 | #152,989 | -11.4% |
| Count | 122 | 105 | -13.9% |
| Per 100K | 0.04 | 0.04 | -12.2% |
Between the 2010 and 2020 Census, the number of Deffley bearers went from 122 to 105 (-13.9% change). The surname moved down 15,662 positions in the national ranking, going from #137,327 to #152,989.
FAQ
Deffley surname: questions and answers
How many people in the U.S. have the surname Deffley?
Name Census estimates that about 120 living Americans carry the surname Deffley. Using the current population baseline, that works out to roughly 1 in 2,856,286 residents.
How common is Deffley?
Deffley ranks #152,989 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 105 people with the surname Deffley. That is different from the site's living-bearer estimate (120), 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 Deffley.
Has Deffley become more or less common over time?
Between 2010 and 2020, the surname Deffley went from 122 recorded bearers to 105. That is a decrease of 17 (-13.9%). In the national ranking it fell from #137,327 to #152,989.
What does the Census say about the background of Deffley?
Among Census respondents with the surname Deffley, the largest self-reported group is White at 92.4%. The next largest groups are Hispanic (5.7%) and Asian/Pacific Islander (1.0%). 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 Deffley in the 2020 Census, accounting for 92.4% (97 people in the source table).
What is the full ancestry breakdown?
Deffley appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.4%), Hispanic (5.7%), Asian/Pacific Islander (1.0%). 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 Deffley (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 Deffley mean?
A locational surname referring to someone from a place called Deffley or Deffely. 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 Deffley (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 are called Deffley?
Want to know how many people have the last name Deffley? HowManyOfMe.org, our sister site, puts the living-bearer count front and centre.