2000
#2,398
National surname rank
Recorded bearers 13,847
First available Census row
Per 100,000 5.13
Uncommon Last name
Dias
A Portuguese and Spanish surname referring to a person who lived near a ditch or trench.
According to the 2020 US Census Bureau surname tables, roughly 18,914 Americans carry the last name Dias. That puts it at #2,141 in the national surname ranking, appearing at a frequency of 5.52 per 100,000 people (about 1 in 18,122 residents).
This page is the full Name Census profile for the Dias 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 Dias with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
19K
1 in 18,122
Census rank
#2,141
2020 decennial data
Per 100,000
5.5
Frequency rate
Recorded bearers
16K
uncommon in the US
Popularity narrative
The Census Bureau recorded 16,494 bearers of the surname Dias in its 2020 decennial surname file. At a rate of 5.52 per 100,000 residents, it holds the 2141st position in the national surname ranking.
Among Census respondents with the surname Dias, the largest self-reported group is White at 54.6%. The next largest groups are Hispanic (27.3%) and Asian/Pacific Islander (7.2%).
Origin
Meaning and origin of Dias
The surname Dias has its origins in the Iberian Peninsula, specifically in Portugal and Spain. It emerged during the Middle Ages, derived from the Latin word "dies," meaning "day." The name was likely initially given as a personal name, possibly referring to someone born on a specific day or associated with a particular religious feast day.
One of the earliest recorded instances of the surname Dias can be found in the "Livro Velho de Linhagens" (Old Book of Lineages), a medieval Portuguese manuscript dating back to the 13th century. This document mentions several individuals bearing the name Dias, indicating its widespread use in Portugal during that period.
In Spain, the surname Dias is closely linked to the region of Galicia, where it is believed to have originated. The earliest known reference to the name in Spain can be traced back to the 12th century, appearing in various historical documents from that era.
Dias is also associated with several notable figures throughout history. One prominent individual was Bartolomeu Dias (c. 1450-1500), a Portuguese explorer who became the first European to sail around the southern tip of Africa, known as the Cape of Good Hope. His pioneering voyage in 1488 paved the way for the eventual establishment of a sea route to India.
Another notable figure was Gonçalo Dias (c. 1420-1475), a Portuguese nobleman and military commander who played a crucial role in the conquest of Alcácer Ceguer in North Africa during the reign of King Afonso V of Portugal.
In the realm of literature, Gomes Dias (c. 1460-1540), a Portuguese poet and playwright, gained recognition for his works such as the play "Tragédia de Inês de Castro" (Tragedy of Inês de Castro).
Additionally, Aleixo Dias (c. 1570-1662), a Portuguese Jesuit missionary and explorer, made significant contributions to the exploration of the Amazon region in Brazil during the 17th century.
Finally, Manuel Dias (c. 1550-1613), a Portuguese architect and military engineer, left his mark on various fortifications and architectural works in Portugal, including the Fortress of São Julião da Barra in Lisbon.
The surname Dias has a rich history spanning centuries, with its roots firmly planted in the Iberian Peninsula. Its bearers have left an indelible mark on various fields, including exploration, literature, military endeavors, and architecture, contributing to the cultural and historical tapestry of Portugal and Spain.
Demographics
Ancestry and ethnicity for Dias
Among Census respondents with the surname Dias, the largest self-reported group is White at 54.6%. The next largest groups are Hispanic (27.3%) and Asian/Pacific Islander (7.2%).
The bar chart below shows how Dias 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 Dias surname at the time of the 2020 Census, not any inherent property of the name itself.
- White54.6% · 9,008
- Hispanic or Latino27.3% · 4,501
- Asian and Pacific Islander7.2% · 1,183
- Black or African American6.8% · 1,119
- Two or more races3.7% · 617
- American Indian and Alaska Native0.4% · 66
Timeline
Historical Census data for Dias
Dias 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
#2,266
National surname rank
Recorded bearers 16,044
+2,197 bearers (+15.9%)
Per 100,000 5.44
Rank movement Up 132 places
2020
#2,141
National surname rank
Recorded bearers 16,494
+450 bearers (+2.8%)
Per 100,000 5.52
Rank movement Up 125 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #2,398 | 13,847 | 5.13 | First available Census row | First available Census row |
| 2010 | #2,266 | 16,044 | 5.44 | +2,197 bearers (+15.9%) | Up 132 places |
| 2020 | #2,141 | 16,494 | 5.52 | +450 bearers (+2.8%) | Up 125 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 Dias 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 | #2,266 | #2,141 | 5.5% |
| Count | 16,044 | 16,494 | 2.8% |
| Per 100K | 5.44 | 5.52 | 1.4% |
Between the 2010 and 2020 Census, the number of Dias bearers went from 16,044 to 16,494 (+2.8% change). The surname moved up 125 positions in the national ranking, going from #2,266 to #2,141.
FAQ
Dias surname: questions and answers
How many people in the U.S. have the surname Dias?
Name Census estimates that about 18,914 living Americans carry the surname Dias. Using the current population baseline, that works out to roughly 1 in 18,122 residents.
How common is Dias?
Dias ranks #2,141 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 5.52 per 100,000 residents, which is about 6 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 16,494 people with the surname Dias. That is different from the site's living-bearer estimate (18,914), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 5.52 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 5.52 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 6 of them to have the surname Dias.
Has Dias become more or less common over time?
Between 2010 and 2020, the surname Dias went from 16,044 recorded bearers to 16,494. That is an increase of 450 (+2.8%). In the national ranking it rose from #2,266 to #2,141.
What does the Census say about the background of Dias?
Among Census respondents with the surname Dias, the largest self-reported group is White at 54.6%. The next largest groups are Hispanic (27.3%) and Asian/Pacific Islander (7.2%). 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 Dias in the 2020 Census, accounting for 54.6% (9,008 people in the source table).
What is the full ancestry breakdown?
Dias appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (54.6%), Hispanic (27.3%), Asian/Pacific Islander (7.2%). 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 Dias (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 Dias mean?
A Portuguese and Spanish surname referring to a person who lived near a ditch or trench. 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 Dias (5.52 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 common is the surname Dias?
Our sister site HowManyOfMe.org answers how many people have the last name Dias at a glance, with the living-bearer count up front.