2010
#157,234
National surname rank
Recorded bearers 103
First available Census row
Per 100,000 0.03
Very Rare Last name
Ionno
An Italian surname derived from the phrase "Io non lo so" meaning "I don't know."
According to the 2020 US Census Bureau surname tables, roughly 117 Americans carry the last name Ionno. That puts it at #154,755 in the national surname ranking, appearing at a frequency of 0.03 per 100,000 people (about 1 in 2,929,524 residents).
This page is the full Name Census profile for the Ionno 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
117
1 in 2,929,524
Census rank
#154,755
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
102
very rare in the US
Popularity narrative
The Census Bureau recorded 102 bearers of the surname Ionno in its 2020 decennial surname file. At a rate of 0.03 per 100,000 residents, it holds the 154755th position in the national surname ranking.
Among Census respondents with the surname Ionno, the largest self-reported group is White at 89.2%. The next largest groups are Two or More Races (4.9%) and Black (3.9%).
Origin
Meaning and origin of Ionno
The surname IONNO has its origins in Italy, specifically in the region of Campania. It is believed to have emerged during the late Middle Ages, around the 13th or 14th century. The name is thought to derive from the Italian word "ionno," which means "blonde" or "fair-haired," suggesting that the original bearer of this surname may have had distinct physical features.
One of the earliest recorded instances of the name IONNO can be found in the historic city of Naples, where several families bearing this surname were documented in the 16th and 17th centuries. The name was particularly prevalent in the town of Portici, located near the famous Mount Vesuvius.
In the late 16th century, a man named Giovan Battista IONNO (1568-1642) gained prominence as a skilled architect and engineer. He was responsible for designing several notable buildings in Naples, including the Church of San Giuseppe delle Monache and the Palazzo Zevallos Stigliano.
Another prominent figure with the surname IONNO was Giuseppe IONNO (1692-1768), a renowned painter from the town of Portici. His works, which often depicted religious scenes and landscapes, can still be found in various churches and museums throughout the Campania region.
During the 18th century, the IONNO family produced a notable scholar and philosopher named Antonio IONNO (1723-1798). He was a professor at the University of Naples and wrote extensively on topics ranging from metaphysics to natural philosophy.
In the 19th century, a man named Vincenzo IONNO (1819-1891) gained recognition as a successful entrepreneur and businessman. He founded a successful textile factory in Naples, which employed hundreds of workers and contributed significantly to the local economy.
Another noteworthy individual with the surname IONNO was Maria IONNO (1875-1952), a renowned opera singer who performed in various theaters across Italy and Europe. She was particularly celebrated for her roles in the operas of Verdi and Puccini.
Over the centuries, the surname IONNO has spread beyond its origins in Campania, with families bearing this name found in various parts of Italy and even in other countries. However, its roots can be traced back to the historic region of Campania, where it emerged as a distinctive surname reflecting the physical characteristics of its earliest bearers.
Demographics
Ancestry and ethnicity for Ionno
Among Census respondents with the surname Ionno, the largest self-reported group is White at 89.2%. The next largest groups are Two or More Races (4.9%) and Black (3.9%).
The bar chart below shows how Ionno 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 Ionno surname at the time of the 2020 Census, not any inherent property of the name itself.
- White89.2% · 91
- Two or more races4.9% · 5
- Black or African American3.9% · 4
- Hispanic or Latino2.0% · 2
Timeline
Historical Census data for Ionno
Ionno appears in 2 published Census surname files: 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2020
#154,755
National surname rank
Recorded bearers 102
-1 bearers (-1.0%)
Per 100,000 0.03
Rank movement Up 2,479 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2010 | #157,234 | 103 | 0.03 | First available Census row | First available Census row |
| 2020 | #154,755 | 102 | 0.03 | -1 bearers (-1.0%) | Up 2,479 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 Ionno 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 | #157,234 | #154,755 | 1.6% |
| Count | 103 | 102 | -1.0% |
| Per 100K | 0.03 | 0.03 | 13.8% |
Between the 2010 and 2020 Census, the number of Ionno bearers went from 103 to 102 (-1.0% change). The surname moved up 2,479 positions in the national ranking, going from #157,234 to #154,755.
FAQ
Ionno surname: questions and answers
How many people in the U.S. have the surname Ionno?
Name Census estimates that about 117 living Americans carry the surname Ionno. Using the current population baseline, that works out to roughly 1 in 2,929,524 residents.
How common is Ionno?
Ionno ranks #154,755 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 102 people with the surname Ionno. That is different from the site's living-bearer estimate (117), 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 Ionno.
Has Ionno become more or less common over time?
Between 2010 and 2020, the surname Ionno went from 103 recorded bearers to 102. That is a decrease of 1 (-1.0%). In the national ranking it rose from #157,234 to #154,755.
What does the Census say about the background of Ionno?
Among Census respondents with the surname Ionno, the largest self-reported group is White at 89.2%. The next largest groups are Two or More Races (4.9%) and Black (3.9%). 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 Ionno in the 2020 Census, accounting for 89.2% (91 people in the source table).
What is the full ancestry breakdown?
Ionno appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (89.2%), Two or More Races (4.9%), Black (3.9%). 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 Ionno (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 Ionno mean?
An Italian surname derived from the phrase "Io non lo so" meaning "I don't know." 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 Ionno (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 many people are called Ionno?
Want to know how common the surname Ionno is? HowManyOfMe.org, our sister site, puts the living-bearer count front and centre.