Cillian Boy
How popular is Cillian?
#507 boy name in 2025
595 baby boys were named Cillian in the US in 2025, making it the 507th most popular boy name.
4,073living people named Cillian (est.)
4median age of people named Cillian
4,090babies named Cillian since 1880
1 in 5,572US babies born in 2025
Cillian popularity over time
Boys Girls
| Rank in 2025 | #507 for boys (▼ 44 from 2024) |
|---|---|
| Babies in 2025 | 595 boys |
| 10-year trend | Rising fast (+392% babies vs 2015) |
| Earlier ranks | #1,416 in 2015, #957 in 2020 |
| Peak year | 2024 (668 boys) |
| Highest rank | #463 in 2024 |
| First recorded | 1995 |
| Boys vs girls (last 10 years) | 100% boys, 0% girls |
| Chance a classmate shares it | 0.4% in a class of 25 kids born in 2025 |
Where Cillian is most popular
Babies named Cillian per 1,000 boys born in each state, 2021 to 2025. Darker means more common.
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- Alaska: 0.8 per 1,000 (10 boys)
- Massachusetts: 0.8 per 1,000 (115 boys)
- New Hampshire: 0.7 per 1,000 (15 boys)
- Rhode Island: 0.6 per 1,000 (10 boys)
- Connecticut: 0.6 per 1,000 (38 boys)
Cillian by decade
Boy names about as popular as Cillian
Questions
- Is Cillian a boy or girl name?
- Cillian is mostly a boy name. Over the last 10 years, 100% of babies named Cillian were boys.
- How popular is the name Cillian?
- 595 baby boys were named Cillian in the US in 2025, making it the 507th most popular boy name.
- When was Cillian most popular?
- Cillian peaked in 2024, when 668 boys were given the name. Its highest rank was #463 in 2024.
- How many people are named Cillian?
- 4,090 babies have been named Cillian in the US since 1880. We estimate about 4,073 of them are alive in 2026, with a median age of 4.
- Where is Cillian most popular?
- From 2021 to 2025, Cillian was most common in Alaska, at 0.8 of every 1,000 boys born there.
Source: Social Security Administration baby name data, 1880 to 2025 (names given to at least 5 babies of a sex in a year). Living-people and median-age figures are our estimates using US life tables. How we calculate.