2000
#13,820
National surname rank
Recorded bearers 2,008
First available Census row
Per 100,000 0.74
Rare Last name
Guglielmo
An Italian surname derived from the Germanic name Wilhelm, meaning "resolute protection."
According to the 2020 US Census Bureau surname tables, roughly 2,249 Americans carry the last name Guglielmo. That puts it at #14,586 in the national surname ranking, appearing at a frequency of 0.66 per 100,000 people (about 1 in 152,403 residents).
This page is the full Name Census profile for the Guglielmo 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
2.2K
1 in 152,403
Census rank
#14,586
2020 decennial data
Per 100,000
0.7
Frequency rate
Recorded bearers
2.0K
rare in the US
Popularity narrative
The Census Bureau recorded 1,961 bearers of the surname Guglielmo in its 2020 decennial surname file. At a rate of 0.66 per 100,000 residents, it holds the 14586th position in the national surname ranking.
Among Census respondents with the surname Guglielmo, the largest self-reported group is White at 91.9%. The next largest groups are Hispanic (6.0%) and Two or More Races (1.5%).
Origin
Meaning and origin of Guglielmo
The surname Guglielmo originated in Italy during the medieval period. It is derived from the Italian form of the Germanic name Wilhelm, which means "resolute protector." The name was particularly prevalent in the regions of Tuscany and Umbria.
One of the earliest recorded instances of the surname Guglielmo can be found in the Codice Diplomatico Longobardo, a collection of historical documents from the Lombard period in Italy, dating back to the 8th century. The name appears in various forms, such as Guglielmi, Guglielmus, and Guglielmino.
In the 13th century, a notable figure bearing the name Guglielmo was Guglielmo da Piacenza, a renowned jurist and legal scholar who contributed significantly to the development of canon law. He lived from around 1210 to 1271.
Another historical figure with the surname Guglielmo was Guglielmo Marcillat, a French soldier and diplomat who served as the ambassador of King Charles VIII to the Ottoman Empire in the late 15th century. He played a crucial role in negotiating the Treaty of Tours in 1497.
During the Renaissance period, Guglielmo della Porta, an Italian sculptor and architect, left his mark on the city of Rome. He was born in 1515 and passed away in 1577. His works included the famous Palazzo dei Conservatori and the Palazzo dei Governatori in the Piazza del Campidoglio.
In the realm of literature, Guglielmo Ferrero, an Italian historian and novelist, gained recognition for his works, including "Greatness and Decline of Rome" and "The Reconstruction of Ancient Thought." He was born in 1871 and died in 1942.
Another noteworthy figure was Guglielmo Marconi, the Italian inventor and electrical engineer who pioneered the development of long-distance radio transmission. He was awarded the Nobel Prize in Physics in 1909 for his groundbreaking contributions. Marconi was born in 1874 and passed away in 1937.
Demographics
Ancestry and ethnicity for Guglielmo
Among Census respondents with the surname Guglielmo, the largest self-reported group is White at 91.9%. The next largest groups are Hispanic (6.0%) and Two or More Races (1.5%).
The bar chart below shows how Guglielmo 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 Guglielmo surname at the time of the 2020 Census, not any inherent property of the name itself.
- White91.9% · 1,803
- Hispanic or Latino6.0% · 117
- Two or more races1.5% · 29
- Asian and Pacific Islander0.5% · 10
- Black or African American0.1% · 2
Timeline
Historical Census data for Guglielmo
Guglielmo 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
#14,382
National surname rank
Recorded bearers 2,078
+70 bearers (+3.5%)
Per 100,000 0.70
Rank movement Down 562 places
2020
#14,586
National surname rank
Recorded bearers 1,961
-117 bearers (-5.6%)
Per 100,000 0.66
Rank movement Down 204 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #13,820 | 2,008 | 0.74 | First available Census row | First available Census row |
| 2010 | #14,382 | 2,078 | 0.70 | +70 bearers (+3.5%) | Down 562 places |
| 2020 | #14,586 | 1,961 | 0.66 | -117 bearers (-5.6%) | Down 204 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 Guglielmo 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 | #14,382 | #14,586 | -1.4% |
| Count | 2,078 | 1,961 | -5.6% |
| Per 100K | 0.70 | 0.66 | -6.3% |
Between the 2010 and 2020 Census, the number of Guglielmo bearers went from 2,078 to 1,961 (-5.6% change). The surname moved down 204 positions in the national ranking, going from #14,382 to #14,586.
FAQ
Guglielmo surname: questions and answers
How many people in the U.S. have the surname Guglielmo?
Name Census estimates that about 2,249 living Americans carry the surname Guglielmo. Using the current population baseline, that works out to roughly 1 in 152,403 residents.
How common is Guglielmo?
Guglielmo ranks #14,586 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 0.66 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 1,961 people with the surname Guglielmo. That is different from the site's living-bearer estimate (2,249), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.66 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.66 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 Guglielmo.
Has Guglielmo become more or less common over time?
Between 2010 and 2020, the surname Guglielmo went from 2,078 recorded bearers to 1,961. That is a decrease of 117 (-5.6%). In the national ranking it fell from #14,382 to #14,586.
What does the Census say about the background of Guglielmo?
Among Census respondents with the surname Guglielmo, the largest self-reported group is White at 91.9%. The next largest groups are Hispanic (6.0%) and Two or More Races (1.5%). 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 Guglielmo in the 2020 Census, accounting for 91.9% (1,803 people in the source table).
What is the full ancestry breakdown?
Guglielmo appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (91.9%), Hispanic (6.0%), Two or More Races (1.5%). 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 Guglielmo (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 Guglielmo mean?
An Italian surname derived from the Germanic name Wilhelm, meaning "resolute protection." 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 Guglielmo (0.66 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 are called Guglielmo?
See how many Americans have the surname Guglielmo on HowManyOfMe.org, our sister site built around that single question.