Rank among US baby names by birth year, 1995–2025. Lower is more popular; the scale is logarithmic so the top of the chart is not compressed.
More children were named Cillian in 2024 than in any other year — 674 of them. It first clears the SSA reporting threshold in 1995. In 2025 it ranked #507 with 595 births.
Compared with 2015, births are up 4.9×. Year on year the rank dropped by 44.
Recorded US births by year. The peak is labelled; the axis starts at zero.
How many people are named Cillian?
An estimated 4,100 living Americans are called Cillian.
This is a survival-weighted estimate, not a headcount: every recorded birth year is
multiplied by the chance someone born that year is still alive, using the SSA period life table.
How the estimate works.
How old is the average Cillian?
The typical living Cillian is 3 years old. Most living bearers were born in the 2020s. By the site’s era rules that makes Cillian a current name.
Your Cillian
Estimated living bearers by age today. Each bar is a birth year, weighted by the chance someone born then is still alive.
Where Cillian is most common
Cillian is 3.4× as common in Massachusetts as it is nationally. Connecticut, New York and Pennsylvania follow.
Same as national3× or more
Location quotient, 2016–2025. Shaded states use the name more than the country does, relative to their own births. Exact figures are in the table below.
States where Cillian is over-represented, 2016–2025.
The location quotient compares the state's share of the name with the national share.
