2000
#7,265
National surname rank
Recorded bearers 4,235
First available Census row
Per 100,000 1.57
Rare Last name
Decastro
Of Spanish and Portuguese origin, meaning "of the castle," referring to someone who lived or worked at a castle.
According to the 2020 US Census Bureau surname tables, roughly 6,754 Americans carry the last name Decastro. That puts it at #5,675 in the national surname ranking, appearing at a frequency of 1.97 per 100,000 people (about 1 in 50,748 residents).
This page is the full Name Census profile for the Decastro 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 Decastro with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
6.8K
1 in 50,748
Census rank
#5,675
2020 decennial data
Per 100,000
2.0
Frequency rate
Recorded bearers
5.9K
rare in the US
Popularity narrative
The Census Bureau recorded 5,890 bearers of the surname Decastro in its 2020 decennial surname file. At a rate of 1.97 per 100,000 residents, it holds the 5675th position in the national surname ranking.
Among Census respondents with the surname Decastro, the largest self-reported group is Asian/Pacific Islander at 37.6%. The next largest groups are White (30.1%) and Hispanic (24.2%).
Origin
Meaning and origin of Decastro
The surname DeCastro originates from Spain and Portugal, with its roots dating back to the medieval period. It is derived from the Latin term "castrum," which means "fortified place" or "castle." This connection suggests that the name may have been initially associated with families who lived near or owned castles or fortified towns.
In Spain, the DeCastro surname can be traced back to the 11th century, with references found in historical records from the kingdoms of León and Castile. One of the earliest documented instances of the name appears in the Becerro de las Behetrías, a medieval census conducted in the 14th century during the reign of King Pedro I of Castile.
The DeCastro family was influential in the Iberian Peninsula during the Middle Ages and the Renaissance. Notable figures include Doña Inés de Castro, a Galician noblewoman who became the mistress of King Pedro I of Portugal in the 14th century. Their tragic love story has been celebrated in literature and folklore.
In the 15th century, Fernando de Castro y Andrade, also known as El Conde de Lemos, was a prominent military leader and diplomat who served under the Catholic Monarchs, Isabella I of Castile and Ferdinand II of Aragon. He played a crucial role in the conquest of Granada, the last Moorish stronghold in Spain.
Another notable figure is Lope de Castro, a Spanish conquistador born in 1516, who participated in the conquest of Peru alongside Francisco Pizarro. He later became the governor of Florida and established the first European settlement in the region, the short-lived Santa María del Punta.
In the realm of literature, Guillem de Castro y Bellvis was a 17th-century Spanish playwright renowned for his works, including "Las Mocedades del Cid" and "Las Hazañas del Cid," which dramatized the life of the legendary Castilian hero El Cid Campeador.
As the DeCastro family expanded and migrated, the name spread to other parts of the world, particularly to the Americas during the Spanish colonization. Despite its widespread presence, the surname maintains its connection to its Spanish and Portuguese origins, reflecting the historical significance of castles and fortified settlements in the Iberian Peninsula.
Demographics
Ancestry and ethnicity for Decastro
Among Census respondents with the surname Decastro, the largest self-reported group is Asian/Pacific Islander at 37.6%. The next largest groups are White (30.1%) and Hispanic (24.2%).
The bar chart below shows how Decastro 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 Decastro surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander37.6% · 2,217
- White30.1% · 1,774
- Hispanic or Latino24.2% · 1,423
- Black or African American3.9% · 232
- Two or more races3.9% · 232
- American Indian and Alaska Native0.2% · 12
Timeline
Historical Census data for Decastro
Decastro 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
#6,361
National surname rank
Recorded bearers 5,354
+1,119 bearers (+26.4%)
Per 100,000 1.82
Rank movement Up 904 places
2020
#5,675
National surname rank
Recorded bearers 5,890
+536 bearers (+10.0%)
Per 100,000 1.97
Rank movement Up 686 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #7,265 | 4,235 | 1.57 | First available Census row | First available Census row |
| 2010 | #6,361 | 5,354 | 1.82 | +1,119 bearers (+26.4%) | Up 904 places |
| 2020 | #5,675 | 5,890 | 1.97 | +536 bearers (+10.0%) | Up 686 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 Decastro 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 | #6,361 | #5,675 | 10.8% |
| Count | 5,354 | 5,890 | 10.0% |
| Per 100K | 1.82 | 1.97 | 8.3% |
Between the 2010 and 2020 Census, the number of Decastro bearers went from 5,354 to 5,890 (+10.0% change). The surname moved up 686 positions in the national ranking, going from #6,361 to #5,675.
FAQ
Decastro surname: questions and answers
How many people in the U.S. have the surname Decastro?
Name Census estimates that about 6,754 living Americans carry the surname Decastro. Using the current population baseline, that works out to roughly 1 in 50,748 residents.
How common is Decastro?
Decastro ranks #5,675 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.97 per 100,000 residents, which is about 2 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 5,890 people with the surname Decastro. That is different from the site's living-bearer estimate (6,754), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.97 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.97 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 2 of them to have the surname Decastro.
Has Decastro become more or less common over time?
Between 2010 and 2020, the surname Decastro went from 5,354 recorded bearers to 5,890. That is an increase of 536 (+10.0%). In the national ranking it rose from #6,361 to #5,675.
What does the Census say about the background of Decastro?
Among Census respondents with the surname Decastro, the largest self-reported group is Asian/Pacific Islander at 37.6%. The next largest groups are White (30.1%) and Hispanic (24.2%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Decastro in the 2020 Census, accounting for 37.6% (2,217 people in the source table).
What is the full ancestry breakdown?
Decastro appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (37.6%), White (30.1%), Hispanic (24.2%). 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 Decastro (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 Decastro mean?
Of Spanish and Portuguese origin, meaning "of the castle," referring to someone who lived or worked at a castle. 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 Decastro (1.97 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 Decastro?
You can see how many people are called Decastro on our sister site HowManyOfMe.org — same data roots, lighter UI.