Compare two names
Cillian and Killian side by side: Cillian peaked in 2024 and Killian in 2017; in 2025 they were given to 595 and 785 babies.
Cillian and Killian, year by year
Girls and boys together; Cillian solid, Killian dashed.
| Cillian | Killian | |
|---|---|---|
| Births 2025 | 595 | 785 |
| Rank 2025 | #507 among boys’ names | #418 among boys’ names |
| Recorded since 1880 | 4,090 | 16,834 |
| Peak year | 2024 | 2017 |
| Girls | 0.1% | 4% |
| Alive, estimated | 4,060 | 16,600 |
| Median age | 4 | 9 |
Both names: SSA national file, published May 8, 2026, and SSA’s cohort life tables.