2000
#29,662
National surname rank
Recorded bearers 749
First available Census row
Per 100,000 0.28
Very Rare Last name
Dillehay
From a valley between hills or meadowlands near cultivated fields.
According to the 2020 US Census Bureau surname tables, roughly 828 Americans carry the last name Dillehay. That puts it at #33,884 in the national surname ranking, appearing at a frequency of 0.24 per 100,000 people (about 1 in 413,955 residents).
This page is the full Name Census profile for the Dillehay 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
828
1 in 413,955
Census rank
#33,884
2020 decennial data
Per 100,000
0.2
Frequency rate
Recorded bearers
722
very rare in the US
Popularity narrative
The Census Bureau recorded 722 bearers of the surname Dillehay in its 2020 decennial surname file. At a rate of 0.24 per 100,000 residents, it holds the 33884th position in the national surname ranking.
Among Census respondents with the surname Dillehay, the largest self-reported group is White at 88.4%. The next largest groups are Hispanic (4.7%) and Two or More Races (3.3%).
Origin
Meaning and origin of Dillehay
The surname Dillehay is of Old French origin, derived from the Old French words "de l'hay" or "du l'hay," meaning "from the hedge" or "from the enclosed land." It is believed to have originated as a locational name for someone who lived near a hedged or enclosed area.
The earliest recorded instances of the name can be traced back to the late 12th century in the regions of Normandy and Picardy in northern France. It was likely introduced to England after the Norman Conquest in 1066, when many Norman families settled in various parts of the country.
In the Hundred Rolls of Huntingdonshire, a census-like record from the 13th century, the name appears as "de la Haye." This spelling variation highlights the name's connection to the Old French term "de l'hay."
One of the earliest known bearers of the name was Sir Robert de la Haye, a Norman knight who fought alongside William the Conqueror during the Battle of Hastings in 1066. He was rewarded with land in Lincolnshire, where his descendants continued to use the name.
Another notable figure was Sir John de la Haye, a 14th-century English diplomat and soldier who served under Edward III during the Hundred Years' War. He played a significant role in the Battle of Crécy in 1346 and was later appointed as the Lord Warden of the Cinque Ports.
In the 16th century, a branch of the family settled in the village of Dillehay in Somerset, England, where the name likely evolved to its current spelling of Dillehay. This village name itself is derived from the Old English words "dill" (a type of herb) and "hay" (an enclosed area).
Notable individuals with the surname Dillehay include William Dillehay (1792-1870), an American politician and lawyer who served as a member of the United States House of Representatives from Tennessee, and Tom Dillehay (born 1945), an American anthropologist and archaeologist known for his work on the peopling of the Americas.
Other historical figures bearing the Dillehay surname include Joseph Dillehay (1757-1820), a Revolutionary War soldier from Pennsylvania, and James Dillehay (1818-1894), a Baptist minister and educator from Virginia who served as the president of Hollins University.
Demographics
Ancestry and ethnicity for Dillehay
Among Census respondents with the surname Dillehay, the largest self-reported group is White at 88.4%. The next largest groups are Hispanic (4.7%) and Two or More Races (3.3%).
The bar chart below shows how Dillehay 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 Dillehay surname at the time of the 2020 Census, not any inherent property of the name itself.
- White88.4% · 638
- Hispanic or Latino4.7% · 34
- Two or more races3.3% · 24
- Black or African American2.8% · 20
- Asian and Pacific Islander0.7% · 5
- American Indian and Alaska Native0.1% · 1
Timeline
Historical Census data for Dillehay
Dillehay 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
#31,412
National surname rank
Recorded bearers 737
-12 bearers (-1.6%)
Per 100,000 0.25
Rank movement Down 1,750 places
2020
#33,884
National surname rank
Recorded bearers 722
-15 bearers (-2.0%)
Per 100,000 0.24
Rank movement Down 2,472 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #29,662 | 749 | 0.28 | First available Census row | First available Census row |
| 2010 | #31,412 | 737 | 0.25 | -12 bearers (-1.6%) | Down 1,750 places |
| 2020 | #33,884 | 722 | 0.24 | -15 bearers (-2.0%) | Down 2,472 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 Dillehay 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 | #31,412 | #33,884 | -7.9% |
| Count | 737 | 722 | -2.0% |
| Per 100K | 0.25 | 0.24 | -3.4% |
Between the 2010 and 2020 Census, the number of Dillehay bearers went from 737 to 722 (-2.0% change). The surname moved down 2,472 positions in the national ranking, going from #31,412 to #33,884.
FAQ
Dillehay surname: questions and answers
How many people in the U.S. have the surname Dillehay?
Name Census estimates that about 828 living Americans carry the surname Dillehay. Using the current population baseline, that works out to roughly 1 in 413,955 residents.
How common is Dillehay?
Dillehay ranks #33,884 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.24 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 722 people with the surname Dillehay. That is different from the site's living-bearer estimate (828), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.24 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.24 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 Dillehay.
Has Dillehay become more or less common over time?
Between 2010 and 2020, the surname Dillehay went from 737 recorded bearers to 722. That is a decrease of 15 (-2.0%). In the national ranking it fell from #31,412 to #33,884.
What does the Census say about the background of Dillehay?
Among Census respondents with the surname Dillehay, the largest self-reported group is White at 88.4%. The next largest groups are Hispanic (4.7%) and Two or More Races (3.3%). 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 Dillehay in the 2020 Census, accounting for 88.4% (638 people in the source table).
What is the full ancestry breakdown?
Dillehay appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (88.4%), Hispanic (4.7%), Two or More Races (3.3%). 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 Dillehay (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 Dillehay mean?
From a valley between hills or meadowlands near cultivated fields. 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 Dillehay (0.24 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 share the surname Dillehay?
For a quick modern estimate, our sister site HowManyOfMe.org answers that in one glance, with the living-bearer count front and centre.