Cillian is a moderately popular boys' name in England & Wales, ranking #177 in 2024 with 285 recorded births. The name reached its all-time peak in 2024 with 285 births ranking #177. Since 1996, the popularity has increased by 2,275.0%. In 2024, approximately 1 in every 975 boys born was named Cillian. RISING Recent data shows the name is currently rising.