There are an estimated 4,053 people named Cillian alive worldwide today. That ranks Cillian at #4136 globally, with the highest concentrations in United States.
In the United States, Cillian is held by approximately 4,053 people, ranking #4136 among first names. That works out to roughly 1 per 100,000 Americans (or 1 in 81,890 U.S. residents).
Historically Cillian is used overwhelmingly as a male name (99.9% male).
Cillian appears in birth records going back to 1880. Use the chart below to see how its popularity has changed across decades, and the surname section to find common pairings.