2000
#31,389
National surname rank
Recorded bearers 698
First available Census row
Per 100,000 0.26
Rare Last name
Dia
A Spanish surname potentially indicating a person born on Christmas day.
According to the 2020 US Census Bureau surname tables, roughly 2,043 Americans carry the last name Dia. That puts it at #15,770 in the national surname ranking, appearing at a frequency of 0.60 per 100,000 people (about 1 in 167,770 residents).
This page is the full Name Census profile for the Dia 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
2.0K
1 in 167,770
Census rank
#15,770
2020 decennial data
Per 100,000
0.6
Frequency rate
Recorded bearers
1.8K
rare in the US
Popularity narrative
The Census Bureau recorded 1,782 bearers of the surname Dia in its 2020 decennial surname file. At a rate of 0.60 per 100,000 residents, it holds the 15770th position in the national surname ranking.
Among Census respondents with the surname Dia, the largest self-reported group is Black at 55.1%. The next largest groups are Hispanic (16.5%) and White (14.6%).
Origin
Meaning and origin of Dia
The surname DIA has its origins in Spain, tracing back to the medieval period. It is believed to have derived from the Spanish word "dia," meaning "day." This name was likely initially used as a descriptive surname, possibly referring to a person born during the day or employed in a daylight occupation.
One of the earliest recorded instances of the surname DIA can be found in the historical records of Catalonia, a region in northeastern Spain, dating back to the 13th century. The name appeared in various medieval documents, such as tax rolls and property deeds, suggesting its widespread use among the local population.
In the 15th century, the surname DIA was also documented in the town of Baeza, located in the province of Jaén, Andalusia. Historical records from this region mention a family named DIA who owned land and played a role in local affairs.
Notable individuals bearing the surname DIA include Juan Dia (1560-1634), a Spanish poet and playwright from Seville, renowned for his works exploring themes of love and spirituality. Another prominent figure was María Dia (1675-1752), a Spanish nun and scholar known for her writings on theology and philosophy.
During the 16th and 17th centuries, the surname DIA appeared in various parts of Spain, including the regions of Aragon, Valencia, and Galicia. This suggests that the name had spread and taken root in different regions, likely due to migration and intermarriage.
In the 18th century, Francisco Dia (1710-1783) was a Spanish military officer who served in the Spanish Army during the War of the Spanish Succession. He achieved distinction for his bravery and leadership on the battlefield.
As the Spanish Empire expanded across the Atlantic, the surname DIA was also carried to the Americas. One notable individual was Pedro Dia (1825-1891), a Chilean politician and diplomat who served as the Minister of Foreign Affairs during the latter part of the 19th century.
While these examples provide a glimpse into the historical presence of the surname DIA, it is important to note that the name's origins and distribution may have been influenced by various factors, including migration patterns, cultural exchanges, and regional variations in spelling and pronunciation.
Demographics
Ancestry and ethnicity for Dia
Among Census respondents with the surname Dia, the largest self-reported group is Black at 55.1%. The next largest groups are Hispanic (16.5%) and White (14.6%).
The bar chart below shows how Dia 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 Dia surname at the time of the 2020 Census, not any inherent property of the name itself.
- Black or African American55.1% · 982
- Hispanic or Latino16.5% · 294
- White14.6% · 261
- Asian and Pacific Islander9.1% · 163
- Two or more races2.8% · 50
- American Indian and Alaska Native1.8% · 32
Timeline
Historical Census data for Dia
Dia 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
#22,471
National surname rank
Recorded bearers 1,145
+447 bearers (+64.0%)
Per 100,000 0.39
Rank movement Up 8,918 places
2020
#15,770
National surname rank
Recorded bearers 1,782
+637 bearers (+55.6%)
Per 100,000 0.60
Rank movement Up 6,701 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #31,389 | 698 | 0.26 | First available Census row | First available Census row |
| 2010 | #22,471 | 1,145 | 0.39 | +447 bearers (+64.0%) | Up 8,918 places |
| 2020 | #15,770 | 1,782 | 0.60 | +637 bearers (+55.6%) | Up 6,701 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 Dia 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 | #22,471 | #15,770 | 29.8% |
| Count | 1,145 | 1,782 | 55.6% |
| Per 100K | 0.39 | 0.60 | 52.9% |
Between the 2010 and 2020 Census, the number of Dia bearers went from 1,145 to 1,782 (+55.6% change). The surname moved up 6,701 positions in the national ranking, going from #22,471 to #15,770.
FAQ
Dia surname: questions and answers
How many people in the U.S. have the surname Dia?
Name Census estimates that about 2,043 living Americans carry the surname Dia. Using the current population baseline, that works out to roughly 1 in 167,770 residents.
How common is Dia?
Dia ranks #15,770 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.60 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 1,782 people with the surname Dia. That is different from the site's living-bearer estimate (2,043), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.6 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.60 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 Dia.
Has Dia become more or less common over time?
Between 2010 and 2020, the surname Dia went from 1,145 recorded bearers to 1,782. That is an increase of 637 (+55.6%). In the national ranking it rose from #22,471 to #15,770.
What does the Census say about the background of Dia?
Among Census respondents with the surname Dia, the largest self-reported group is Black at 55.1%. The next largest groups are Hispanic (16.5%) and White (14.6%). 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 Dia in the 2020 Census, accounting for 55.1% (982 people in the source table).
What is the full ancestry breakdown?
Dia appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Black (55.1%), Hispanic (16.5%), White (14.6%). 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 Dia (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 Dia mean?
A Spanish surname potentially indicating a person born on Christmas 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 Dia (0.60 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 Dia?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.