Killian
Killian was the 418th most popular name for boys in 2025, given to 770 babies. Its best year was 2017, when it ranked 248th with 1,506 babies. Over the last ten years it has moved down 68 places. More babies were named Killian in the 2010s than in any other decade.
Meaning Origin uncertain · Irish
Say it KIL-ee-un /ˈkɪliən/
- Rank in 2025
- #418 boys, down 66 places since 2020
- Babies in 2025
- 770boys
- Girls and boys
- Almost always a boy’s name2021–2025
- Peak year
- 20171,506 babies
- Total since 1880
- 16,834babies recorded
What does the name Killian mean?
Killian is an English spelling of the Irish name Cillian (older Cillén), borne by Saint Kilian, a 7th-century Irish missionary martyred at Würzburg in Germany. The name is usually linked with Old Irish cell, "church" (from Latin cella), or with ceallach, "strife", but neither is confirmed by the sources consulted; Yonge's 1884 gloss "blind" is outdated. It has become popular in Ireland and the US.
Cillian (Irish, “personal name (meaning uncertain)”)
How sure is this? Uncertain. Origin of Cillian not established.
Other explanations you may read: means 'little church'; means 'war, strife'.
Related names: Cillian, Kilian, Kellan.
See also: Irish names.
Sources for this meaning
- Wiktionary, entry 'Killian', Wiktionary (Wikimedia Foundation)
- Charlotte M. Yonge, History of Christian Names, new ed. (1884), index s.v. 'Kilian' (19th-century work; used for dated usage facts only), Macmillan (public domain; Internet Archive scan)
- CMU Pronouncing Dictionary (cmudict), Carnegie Mellon University
Killian popularity since 1880
A few girls are given the name too: 615 since 1986, 15 in 2025.
| Year | Rank (boys) | Babies (boys) |
|---|---|---|
| 2025 | #418 | 770 |
| 2020 | #352 | 899 |
| 2010 | #766 | 293 |
| 2000 | #1,043 | 139 |
| 1990 | #1,221 | 81 |
| 1980 | — | — |
| 1970 | — | — |
| 1960 | — | — |
| 1950 | — | — |
| 1940 | — | — |
| 1930 | — | — |
| 1920 | #4,648 | 5 |
| 1910 | — | — |
| 1900 | — | — |
| 1890 | — | — |
| 1880 | — | — |
How popular is Killian, counting every spelling?
Killian is the most common spelling of a name family that ranked #288 for boys in 2025 once every spelling is counted together, compared with #418 for Killian on its own. Together these spellings went to 1,245 boys in 2025.
| Spelling | Babies 2025 | Official rank | Babies 2021–2025 |
|---|---|---|---|
| Killian | 770 | #418 | 4,381 |
| Kylian | 448 | #624 | 2,961 |
| Kyllian | 21 | #4,801 | 138 |
Spellings count together when they sound the same in American English and are used for the same sex; nicknames and forms that sound different (such as Theo and Theodore) are kept apart. How we group spellings.
How many kids will share the name Killian?
770 of the 3,606,400 babies born in the US in 2025 were named Killian (0.21 per 1,000 births). For a boy named Killian born in 2025, the chance that another child with the same name is in a class of 20 children the same age is under 1 in 50. If every grade liked the name as much as the 2025 babies do, only about one elementary school in 11 (of 430 pupils) would have a child named Killian.
Shares of all registered births (NCHS); classes assumed to be children born the same year. How we estimate this.
How old are people named Killian?
About 16,000 people born in the US named Killian are alive today, with a median age of 9; half are between 5 and 13. That makes Killian a young name: most people with it are children.
Babies given the name each year (SSA) times the share of that birth year still alive (SSA life tables). Counts people born in the US only. Method.
Killian by state
How common Killian was among boys born in each state in 2021–2025. It is notably more common than nationally in Alaska (4.5×), West Virginia (2.2×), South Dakota (2.2×), Idaho (1.9×), New Hampshire (1.9×). It is least common, relative to the national rate, in Maine, California, Hawaii.
Names with a similar history
These names rose and fell in step with Killian: their share of US boys followed the most similar curve since 1880. If you like Killian, they share its era and feel.
Middle names for Killian · Sibling names for Killian
Questions about the name Killian
What does Killian mean?
The origin of Killian is uncertain: Origin of Cillian not established.
How popular is the name Killian?
Killian was the 418th most popular name for boys in 2025, given to 770 babies. Its best year was 2017, when it ranked 248th with 1,506 babies. Over the last ten years it has moved down 68 places. More babies were named Killian in the 2010s than in any other decade.
Is Killian a boy or girl name?
In 2021–2025, almost always a boy’s name given the name Killian in the US.
Where is Killian most popular?
In 2021–2025, Killian was most common in Alaska (2.27 per 1,000 boys), followed by West Virginia and South Dakota.