Io
A feminine name from Greek mythology referring to a priestess seduced by Zeus.
Name Census estimates that about 214 living Americans carry the first name Io. It appears on both sides of the gender split, with 85.6% of registrations being female. The average person named Io today is around 11 years old, and the year with the single highest number of Io births was 2022 (24 babies).
This page is the full Name Census profile for Io. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Io with official rankings and popularity over time.
People living today
214
~ 1 in 1,601,656 Americans
Peak year
2022
24 babies that year
Average age
11
years old
2023 SSA rank
#9,867
Tracked since 2000
Census
Io in the 2020 Census
The 2020 Census recorded 321 people with the first name Io, which placed it at #28,132 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#28,132
National first-name rank
People counted
321
321 in the published race/origin table
Per 100,000
0.1
People with this name in 2020
Largest reported group
White
48.9% of people with this name
Demographics
Ancestry and ethnicity for Io
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Io is White at 48.9%. The next largest groups are Hispanic (22.4%) and Asian/Pacific Islander (12.8%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Io 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 name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Io at the time of the 2020 Census, not any inherent property of the name itself.
- White48.9% · 157
- Hispanic or Latino22.4% · 72
- Asian and Pacific Islander12.8% · 41
- Two or more races10.6% · 34
- Black or African American5.0% · 16
- American Indian and Alaska Native0.3% · 1
Gender
Gender distribution for Io
Io leans heavily female at 85.6% of total registrations, but 31 boys have also been registered with the name over the years, giving it a small but present crossover presence.
Io as a male name
- Ranked #12,949 in 2023
- 5 male births in 2023
- Peak: 2014 (7 births)
Io as a female name
- Ranked #9,867 in 2023
- 10 female births in 2023
- Peak: 2022 (18 births)
2020 Census snapshot
The 2020 Census sex table shows Io on both sides of the split. Of the 322 people counted with this name, 78 were male (24.2%) and 244 were female (75.8%).
Popularity
Io: popularity over time
The SSA tracks Io from the 2000s through to the 2020s, spanning 3 decades of birth certificate data. The biggest single decade for the name was the 2010s, with 109 total registrations. Although the numbers have come down from the 2010s peak, Io remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Io by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Io during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Ios live
Origin
Meaning and history of Io
Io is a given name with its origins in ancient Greek mythology. The name is derived from the Greek word "ion," which means "violet flower." It is closely associated with the mythological figure Io, a priestess of Hera who was turned into a heifer by Zeus to conceal their affair.
The earliest recorded use of the name Io can be traced back to ancient Greek literature, particularly Homer's Iliad and Ovid's Metamorphoses, where the story of Io's transformation is recounted. In these texts, Io is depicted as a tragic figure, subjected to the whims of the gods and ultimately transformed into a wandering, tormented creature.
Throughout the centuries, the name Io has been borne by various notable individuals. One of the earliest recorded examples is Io of Chios, a renowned Greek poet and writer who lived in the 5th century BCE. She is credited with the invention of the literary genre known as "Iambic verse."
In the realm of astronomy, Io is also the name of one of the four largest moons of Jupiter, discovered by Galileo Galilei in 1610. This celestial body was named after the mythological figure, further cementing the name's place in history.
Another famous bearer of the name was Io Chirica (1888-1935), a Romanian poet and writer known for her contributions to the Symbolist movement. Her works explored themes of love, nature, and the human condition, earning her critical acclaim during her lifetime.
Moving into the 20th century, Io Fuller (1923-2015) was an American author and editor who played a significant role in the Science Fiction and Fantasy genres. She co-founded the prestigious Nebula Awards and served as the president of the Science Fiction and Fantasy Writers of America.
More recently, Io Tillett Wright (born 1986) is an American artist, activist, and television personality known for their work in LGBTQ+ advocacy and representation. Their photography project, "Self Evident Truths," aimed to capture the diversity and resilience of the LGBTQ+ community.
While not an exhaustive list, these examples showcase the rich history and diverse individuals who have borne the name Io throughout the centuries, spanning literature, mythology, astronomy, and various creative fields.
People
Io + last name combinations
How many people share a full name with Io as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with I
Other first names starting with I with a similar number of bearers.
FAQ
Io: questions and answers
How many people in the U.S. are named Io?
Name Census puts the figure at roughly 214 living Americans. We arrive at this by taking every SSA birth registration for Io going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 1,601,656 US residents.
Is Io a common name?
We classify Io as "Very Rare". It ranks above 75.1% of all first names in the SSA dataset by living bearers. Across the full history of the data, 216 babies have been registered with this name.
When was Io most popular?
The single biggest year for Io was 2022, when 24 babies received the name. The fact that the average living Io is about 11 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Io in the 2020 Census?
The published 2020 Census first-name tables recorded 321 people with the name Io, or 0.11 per 100,000 residents. That placed it at #28,132 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Io in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Io?
The 2020 Census sex table shows Io on both sides of the split. Of the 322 people counted with this name, 78 were male (24.2%) and 244 were female (75.8%). The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Io?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Io is White at 48.9%. The next largest groups are Hispanic (22.4%) and Asian/Pacific Islander (12.8%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Io most often in the Census?
White is the largest reported group for people named Io in the 2020 Census, accounting for 48.9% (157 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Io in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Io a female name?
Yes, 85.6% of people registered as Io in the SSA data are female. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Io still being used today?
Yes. The SSA still recorded Io in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Io can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many people share the name Io?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.