2000
#127,948
National surname rank
Recorded bearers 123
First available Census row
Per 100,000 0.05
Very Rare Last name
Rillamas
A rare surname possibly derived from a place name or archaic occupation.
According to the 2020 US Census Bureau surname tables, roughly 118 Americans carry the last name Rillamas. That puts it at #154,182 in the national surname ranking, appearing at a frequency of 0.03 per 100,000 people (about 1 in 2,904,698 residents).
This page is the full Name Census profile for the Rillamas 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
118
1 in 2,904,698
Census rank
#154,182
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
103
very rare in the US
Popularity narrative
The Census Bureau recorded 103 bearers of the surname Rillamas in its 2020 decennial surname file. At a rate of 0.03 per 100,000 residents, it holds the 154182nd position in the national surname ranking.
Among Census respondents with the surname Rillamas, the largest self-reported group is Asian/Pacific Islander at 52.4%. The next largest groups are Hispanic (31.1%) and Two or More Races (13.6%).
Origin
Meaning and origin of Rillamas
The surname RILLAMAS has its origins in the Basque region of northern Spain and southwestern France, dating back to the medieval period. It is believed to have derived from the Basque word "errillama," which means "small hill." This name likely originated as a descriptive term for someone who lived near or on a small hillside.
One of the earliest recorded instances of the name RILLAMAS can be found in the Codex Calixtinus, a 12th-century manuscript that served as a guide for pilgrims on the Camino de Santiago. The document mentions a village called "Villa de Rillamas" located along the pilgrimage route in the region of Navarre, Spain.
In the 13th century, a nobleman named Pedro de RILLAMAS was documented as a member of the court of King Alfonso X of Castile. He was known for his diplomatic skills and was sent on missions to negotiate with neighboring kingdoms.
During the 15th century, the name RILLAMAS appeared in various records of the Basque province of Gipuzkoa. One notable individual was Juan de RILLAMAS, a respected architect who designed several churches and monasteries in the region.
In the 16th century, the RILLAMAS family spread to other parts of Spain and the Americas, as explorers and colonists from the Basque Country ventured to the New World. A prominent figure was Martín de RILLAMAS, who served as a governor in the Spanish colony of Nueva Granada (present-day Colombia) in the 1560s.
Another historical figure was María de RILLAMAS, a nun born in the late 17th century in Bilbao, Spain. She became renowned for her charitable work and later founded a convent in the city dedicated to helping the poor and underprivileged.
Over the centuries, variations of the name RILLAMAS emerged, such as Rillamas, Rillamas, and Rillamas, reflecting regional differences in spelling and pronunciation. However, the core meaning and Basque origin of the name have remained consistent throughout its history.
Demographics
Ancestry and ethnicity for Rillamas
Among Census respondents with the surname Rillamas, the largest self-reported group is Asian/Pacific Islander at 52.4%. The next largest groups are Hispanic (31.1%) and Two or More Races (13.6%).
The bar chart below shows how Rillamas 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 Rillamas surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander52.4% · 54
- Hispanic or Latino31.1% · 32
- Two or more races13.6% · 14
- White1.9% · 2
- Black or African American1.0% · 1
Timeline
Historical Census data for Rillamas
Rillamas 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
#137,327
National surname rank
Recorded bearers 122
-1 bearers (-0.8%)
Per 100,000 0.04
Rank movement Down 9,379 places
2020
#154,182
National surname rank
Recorded bearers 103
-19 bearers (-15.6%)
Per 100,000 0.03
Rank movement Down 16,855 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #127,948 | 123 | 0.05 | First available Census row | First available Census row |
| 2010 | #137,327 | 122 | 0.04 | -1 bearers (-0.8%) | Down 9,379 places |
| 2020 | #154,182 | 103 | 0.03 | -19 bearers (-15.6%) | Down 16,855 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 Rillamas 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 | #137,327 | #154,182 | -12.3% |
| Count | 122 | 103 | -15.6% |
| Per 100K | 0.04 | 0.03 | -13.9% |
Between the 2010 and 2020 Census, the number of Rillamas bearers went from 122 to 103 (-15.6% change). The surname moved down 16,855 positions in the national ranking, going from #137,327 to #154,182.
FAQ
Rillamas surname: questions and answers
How many people in the U.S. have the surname Rillamas?
Name Census estimates that about 118 living Americans carry the surname Rillamas. Using the current population baseline, that works out to roughly 1 in 2,904,698 residents.
How common is Rillamas?
Rillamas ranks #154,182 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.03 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 103 people with the surname Rillamas. That is different from the site's living-bearer estimate (118), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.03 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.03 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 Rillamas.
Has Rillamas become more or less common over time?
Between 2010 and 2020, the surname Rillamas went from 122 recorded bearers to 103. That is a decrease of 19 (-15.6%). In the national ranking it fell from #137,327 to #154,182.
What does the Census say about the background of Rillamas?
Among Census respondents with the surname Rillamas, the largest self-reported group is Asian/Pacific Islander at 52.4%. The next largest groups are Hispanic (31.1%) and Two or More Races (13.6%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Rillamas in the 2020 Census, accounting for 52.4% (54 people in the source table).
What is the full ancestry breakdown?
Rillamas appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (52.4%), Hispanic (31.1%), Two or More Races (13.6%). 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 Rillamas (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 Rillamas mean?
A rare surname possibly derived from a place name or archaic occupation. 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 Rillamas (0.03 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 Rillamas?
If you just want to know how common the surname Rillamas is, HowManyOfMe.org gives you the headline number in one glance.