Cillian
2025 SSA
Below 5 births
About Cillian
Cillian is one of the native Irish names that, along with Aiden and Declan, is becoming an unlikely favorite in contemporary America. The Killian spelling has been more popular in the US, but Cillian's star is rising, perhaps thanks to Irish actor Cillian Murphy, star of Oppenheimer and Peaky Blinders.
There are several Saint Cillians, including one who was sent to Bavaria to convert the natives and was martyred for his trouble.
Patrick Woulfe, a Catholic priest who was instrumental in reviving native Irish names in that country after the war for independence from England in the 1920s, theorized that Cillian might also be related to a Gaelic name meaning war.
Cillian is also given to girls.
Pronounced KIL-ee-un.
As of October 2026, Cillian ranked #507 in US births in 2025 SSA, peaked at #463 in 2024, Nameberry popularity #152.
Popularity & trends
Data table
| Year | US rank | Births | Per million |
|---|---|---|---|
| 2014 | #1,733 | 87 | 45.3 |
| 2015 | #1,418 | 121 | 63.1 |
| 2016 | #1,107 | 177 | 93.3 |
| 2017 | #1,126 | 170 | 91.8 |
| 2018 | #1,051 | 193 | 106.3 |
| 2019 | #1,077 | 186 | 103.7 |
| 2020 | #957 | 228 | 132.1 |
| 2021 | #749 | 340 | 194.3 |
| 2022 | #737 | 352 | 201.6 |
| 2023 | #594 | 476 | 278.3 |
| 2024 | #463 | 668 | 387.7 |
| 2025 | #507 | 595 | 348.3 |
World rankings
Similar names
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Cillian on lists
Famous Cillians
- Cillian MurphyBoy
Irish actor
- Cillian SheridanBoy
Irish footballer
- Cillian VallelyBoy
Irish musician of band Lunasa
Cillian in pop culture
- Cillian BoydBoy
character in the Chaos Walking series by Patrick Ness