How Many People Are Named Illiam?
An estimated 40 people in the United States have the first name Illiam. It is almost exclusively a male name. The average bearer is 42 years old, and Illiam peaked in popularity in 1981 with 8 births that year.
Below you will find a full statistical profile of Illiam as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, and state-by-state birth registrations. You can also check how many people share the full name Illiam paired with any surname.
Key Insights
- Illiam is exceptionally rare. Fewer than 100 people with this name are estimated to be alive in the U.S. today.
Estimated Living Americans
40
About 1 in 8,568,858 people in the U.S.
Rarity
Very Rare
Predicted Gender
Male
100.0% confidence
Average Age
42
years old
Peak Year
1981
8 births
Total Registered
42
since 1880
Gender Distribution for Illiam
Illiam is almost exclusively a male name. Out of 42 total births registered, 100.0% were male.
Illiam as a male name
Ranked #7,350 in 1989
6 male births in 1989
Peak: 1981 (8 births)
Illiam: Popularity Over Time
SSA records for Illiam span from the 1970s to the 1980s, covering 2 decades of naming data. The most popular decade for this name was the 1980s, when 37 babies were registered. Illiam remains highly popular today, with recent registration numbers near its historical peak.
Illiam by Decade
How has Illiam tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Illiam + Last Name Combinations
How many people share a full name with Illiam as the first name? Click a combination below to see the estimate, or search any pairing.
Names Similar to Illiam
Other first names starting with I with a similar number of bearers.
Illiam: Questions and Answers
How many people in the U.S. are named Illiam?
We estimate approximately 40 people named Illiam are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 8,568,858 Americans share this first name.
Is Illiam a common name?
Illiam is classified as "Very Rare" and is more popular than 51% of all first names in the SSA database. A total of 42 births have been registered with this name since 1880.
When was Illiam most popular?
Illiam reached peak popularity in 1981, when 8 babies were given this name. The average age of a living person named Illiam is approximately 42 years old, reflecting when the name was most commonly given.
Is Illiam a male name?
Illiam is predominantly male. 100.0% of people with this name are male. See the gender breakdown above for full details.
How many Illiam Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Illiam Smith, Illiam Johnson, Illiam Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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