Cillian Murphy
There are approximately 4 people named Cillian Murphy living in the United States today. That makes this name combination very rare, occurring at a rate of about 1 in 85,688,585 Americans.
This estimate combines SSA birth records for the first name Cillian with Census Bureau frequency data for the surname Murphy. Below you will find a breakdown of both names, including popularity trends, gender data, and ancestry information.
Expected bearers
4
1 in 85,688,585
Named Cillian
3.5K
Alive today
Named Murphy
358K
Alive today
US population
343M
Denominator
Estimated living: 3.5K
Rarity: Rare
Gender: Male
Peak year: 2024
Average age: 7
Estimated bearers: 358K
Rarity: Common
Census rank: #64
Per 100K: 104.56
Top ancestry: White (83.1%)
First name trend
Cillian: popularity over time
Year-by-year SSA birth registrations for the first name Cillian. The peak year was 2024 with 674 births. The average person named Cillian today is 7 years old.
Babies born per year
Ethnicity
Ancestry of the Murphy surname
Self-reported race and ethnicity breakdown for people with the surname Murphy, from the 2010 US Census Bureau. The largest group is White at 83.1%.
- White83.1%
- Black or African American11.5%
- Hispanic or Latino2.3%
- Two or more races1.8%
- American Indian and Alaska Native0.7%
- Asian and Pacific Islander0.6%
Methodology
How we calculated this
The first name Cillian has a living-bearer frequency of 0.0010% of the US population, based on 3,467 estimated living Americans carrying this first name (from SSA birth records going back to 1880, adjusted for mortality using CDC life tables).
The surname Murphy appears at a rate of 104.56 per 100,000 residents in the 2010 Census Bureau surname file, which translates to a frequency of 0.1046%.
Multiplying these two independent frequencies against the current US population of 342,754,338 gives an expected count of approximately 4 people with the full name Cillian Murphy. This assumes statistical independence between first and last names, which is a simplification but produces reasonable estimates for most combinations.
Related
Other people with the surname Murphy
FAQ
Cillian Murphy: questions and answers
How many people are named Cillian Murphy?
We estimate approximately 4 people in the United States share the full name Cillian Murphy. That works out to about 1 in 85,688,585 Americans. This is calculated by combining the first-name frequency (0.0010%) with the surname frequency (104.56 per 100K) against the current US population.
How rare is the name Cillian Murphy?
We classify Cillian Murphy as "Very Rare". About 1 in 85,688,585 Americans share this exact first and last name combination.
Is Cillian a male or female name?
Cillian is predominantly male. Out of 3,492 total SSA registrations, 99.8% were male and 0.2% were female. See the full Cillian profile for detailed gender data.
Where does this data come from?
First-name data comes from the Social Security Administration's national baby name files (1880 to 2024). Surname data comes from the 2010 US Census Bureau decennial surname tables. Living-bearer estimates use CDC actuarial life tables to adjust for mortality. Read the full methodology.