2000
#18,077
National surname rank
Recorded bearers 1,422
First available Census row
Per 100,000 0.53
Rare Last name
Dy
A Welsh patronymic surname derived from the given name "Dei" or "Day," meaning "son of Dei/Day."
According to the 2020 US Census Bureau surname tables, roughly 2,487 Americans carry the last name Dy. That puts it at #13,421 in the national surname ranking, appearing at a frequency of 0.73 per 100,000 people (about 1 in 137,818 residents).
This page is the full Name Census profile for the Dy 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
2.5K
1 in 137,818
Census rank
#13,421
2020 decennial data
Per 100,000
0.7
Frequency rate
Recorded bearers
2.2K
rare in the US
Popularity narrative
The Census Bureau recorded 2,169 bearers of the surname Dy in its 2020 decennial surname file. At a rate of 0.73 per 100,000 residents, it holds the 13421st position in the national surname ranking.
Among Census respondents with the surname Dy, the largest self-reported group is Asian/Pacific Islander at 85.4%. The next largest groups are White (4.9%) and Hispanic (4.7%).
Origin
Meaning and origin of Dy
The surname "DY" is believed to have originated in England, and it can be traced back to the Middle Ages. It is likely derived from the Old English word "dygge," which means "a ditch or a trench." This suggests that the name may have been given to someone who lived near a ditch or trench, or perhaps someone who worked in the construction or maintenance of ditches and trenches.
One of the earliest recorded instances of the name "DY" can be found in the Domesday Book, a comprehensive survey of land ownership and taxation commissioned by William the Conqueror in 1086. The name appears in various spellings, such as "de Dyke" and "atte Dyke," indicating its association with ditches or dykes.
During the medieval period, the name "DY" was often used as a descriptive surname, referring to the occupation or location of the individual. For example, a person named John Dy may have lived near a ditch or worked as a ditch digger.
In the 13th century, a notable figure with the surname "DY" was Sir William de Dy, a knight who fought in the Crusades under King Richard I. He was born around 1170 and died in 1240.
Another significant person with this surname was Robert Dy, a prominent merchant and landowner who lived in the city of York during the 14th century. He was involved in various trade and business ventures and played an influential role in the city's economic affairs.
In the 16th century, the name "DY" appears in various historical records, including parish registers and tax records. One notable individual from this period was Elizabeth Dy, who was born in 1542 and was a member of the gentry class in Gloucestershire.
During the 17th century, the name "DY" began to spread across different regions of England. One noteworthy figure was Sir Thomas Dy, a Member of Parliament and a respected landowner in Lincolnshire. He was born in 1610 and died in 1678.
The surname "DY" continued to be prevalent in various parts of England throughout the 18th and 19th centuries. One famous individual from this period was William Dy, a renowned poet and playwright born in 1770 in London. His works were widely celebrated and influenced the literary landscape of his time.
Demographics
Ancestry and ethnicity for Dy
Among Census respondents with the surname Dy, the largest self-reported group is Asian/Pacific Islander at 85.4%. The next largest groups are White (4.9%) and Hispanic (4.7%).
The bar chart below shows how Dy 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 Dy surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander85.4% · 1,853
- White4.9% · 106
- Hispanic or Latino4.7% · 103
- Two or more races3.9% · 85
- Black or African American1.0% · 22
Timeline
Historical Census data for Dy
Dy 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
#15,232
National surname rank
Recorded bearers 1,932
+510 bearers (+35.9%)
Per 100,000 0.65
Rank movement Up 2,845 places
2020
#13,421
National surname rank
Recorded bearers 2,169
+237 bearers (+12.3%)
Per 100,000 0.73
Rank movement Up 1,811 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #18,077 | 1,422 | 0.53 | First available Census row | First available Census row |
| 2010 | #15,232 | 1,932 | 0.65 | +510 bearers (+35.9%) | Up 2,845 places |
| 2020 | #13,421 | 2,169 | 0.73 | +237 bearers (+12.3%) | Up 1,811 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 Dy 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 | #15,232 | #13,421 | 11.9% |
| Count | 1,932 | 2,169 | 12.3% |
| Per 100K | 0.65 | 0.73 | 11.6% |
Between the 2010 and 2020 Census, the number of Dy bearers went from 1,932 to 2,169 (+12.3% change). The surname moved up 1,811 positions in the national ranking, going from #15,232 to #13,421.
FAQ
Dy surname: questions and answers
How many people in the U.S. have the surname Dy?
Name Census estimates that about 2,487 living Americans carry the surname Dy. Using the current population baseline, that works out to roughly 1 in 137,818 residents.
How common is Dy?
Dy ranks #13,421 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.73 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 2,169 people with the surname Dy. That is different from the site's living-bearer estimate (2,487), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.73 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.73 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Dy.
Has Dy become more or less common over time?
Between 2010 and 2020, the surname Dy went from 1,932 recorded bearers to 2,169. That is an increase of 237 (+12.3%). In the national ranking it rose from #15,232 to #13,421.
What does the Census say about the background of Dy?
Among Census respondents with the surname Dy, the largest self-reported group is Asian/Pacific Islander at 85.4%. The next largest groups are White (4.9%) and Hispanic (4.7%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Dy in the 2020 Census, accounting for 85.4% (1,853 people in the source table).
What is the full ancestry breakdown?
Dy appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (85.4%), White (4.9%), Hispanic (4.7%). 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 Dy (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 Dy mean?
A Welsh patronymic surname derived from the given name "Dei" or "Day," meaning "son of Dei/Day." 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 Dy (0.73 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 last name Dy?
For a quick modern take, check how many people have the surname Dy on our sister site HowManyOfMe.org.