Name Awesome

Cillian

#507 in 2025Boys' name

Possibly strife

Cillian has been given to 4,090 babies in the U.S. since 1995. In 2025 it ranked #507 of 13,926 boys’ names in use. Its peak year was 2024, with 668 recorded.

Babies named Cillian, 2025

1 in 5,570

Cillian over time, 1880–2025

BoysGirls
020040060080018801900192019401960198020002020

Based on births in the U.S. Babies given the name each year. Hover the chart — or focus it and use the arrow keys — for any year. Gaps mean the name was given fewer than 5 times that year; these counts are unpublished.

Cillian: meaning, origin, and history

Possibly strife

Latin

What Cillian means

Cillian may mean “strife”, associated with ceallach.

Origin, language, and formation

Cillian is used in Alemannic German and Irish. Its origins include Latin.

Cillian comes through Latin Caeciliānus.

Pronunciation and spelling

In Irish, Cillian is pronounced /cɪˈlʲiən̪ˠ/.

American usage and historical context

In the United States, 4,084 boys were recorded with the name Cillian between 1995 and 2025. Its highest annual count was 668 in 2024; its best national rank was #463 in 2024.

Over 5 years its rank rose, from #957 in 2020 to #507 in 2025. Over 10 years its rank rose, from #1,418 in 2015 to #507 in 2025.

In the United States, 6 girls were recorded with the name Cillian between 2024 and 2024. Its highest annual count was 6 in 2024; its best national rank was #13,840 in 2024.

Sources & methodologyReferences, data & attribution

Meaning, origin, and language notes draw on the references below.

American popularity figures use published Social Security Administration records for this exact spelling. Counts below five for a name, sex, and year are omitted.

Wiktionary material is available under CC BY-SA 4.0.

How common is Cillian?

Everything below is computed from the 2025 data — the most recent year available.

Among all babies, 2025
1 in 5,570
595 of 3,315,165 births
Among boys only
1 in 2,870
0.03% of boys
Rank, 2025
#507
of 13,926 boys’ names in use
Coin-flip room size
3,863 kids
Even odds of a second one

Where Cillian sits on the popularity scale

Rarest published (5 a year)#1 — Liam (20,818)

Chance at least one other child shares the name

If the other children were drawn at random from the 2025 national name distribution. Real classrooms cluster by region and community, so treat these as a floor, not a ceiling.

Class of 20Under 1%
Class of 30Under 1%
Grade of 1002%
School of 5009%

Put another way: gather 3,863 children born in 2025 and it's an even bet that one of them is another Cillian. In a class of 30 the chance is Under 1%.

When Cillians were born

Half of everyone ever recorded as Cillian was born before 2022 — so the typical Cillian is around 3 today.

Median birth year
2022
About 3 years old
Biggest decade
2020s
65.2% of all use
Born in the last 25 years
99.8%
A modern name
Recorded since 1950
4,084
People you could plausibly meet
Choose a decade

2020s — 65.2% of all recorded uses (2,662).

Is Cillian rising or falling?

Rank movement and count movement can disagree — the number of distinct names in use keeps growing, so a name holding a steady count still slides down the list. Both are shown.

Rank vs 1 year ago
−44
Places dropped
Rank vs 5 years ago
+450
Places climbed
Rank vs 10 years ago
+911
Places climbed
Births vs 10 years ago
4.92×
More babies than then
Share of its own peak
89.1%
Peak was 2024 (668)
Years since peak
1
Years
Year-to-year steadiness
Volatile
34.2% average annual change
Best rank ever
#463
2024

Spellings of Cillian

Cillian is not the most common spelling — William is, with 96.8% against Cillian's 0.09%.

Grouped by closeness of spelling (up to two letter changes), same sex, with a floor on all-time use. It catches Sophia/Sofia and Aiden/Ayden, and misses spellings that sound alike but look different, like Sean and Shawn.

Where Cillian is used

Across 2016–2025, Cillian was most concentrated in Massachusetts — about 1 in 1,587 boys, against 1 in 5,138 across all states with data. It was least common in Mississippi (1 in 25,000).

463 per 100,000

Most concentrated

  1. 1Massachusetts1 in 1,587
  2. 2Alaska1 in 2,632
  3. 3Connecticut1 in 2,778
  4. 4New York1 in 2,778
  5. 5New Hampshire1 in 2,941
  6. 6Pennsylvania1 in 3,125
  7. 7Colorado1 in 3,333
  8. 8Illinois1 in 3,333

Shading is the share of that state's recorded boys given this name, not the raw count — otherwise the map would just show which states are biggest. Unshaded states have no published records for this period. U.S. birth records suppress state-year counts below 5; state counts therefore don't add up to the national total. Every state links to its full rankings.

Geographically, Cillian is somewhat regional — more concentrated than 63% of the names used widely enough to compare. See the most regional names

Cillian around the world

Where Cillian ranks in official birth records elsewhere in the world. Rankings only — the number of births isn’t comparable between places, so it isn’t shown.

  • England & Wales
    1996–2025
    #217
    in 2025
  • Scotland
    2007–2025
    #100
    in 2025
  • Northern Ireland
    1997–2025
    #11
    in 2025
  • Ireland
    1970–2025
    #9
    in 2025
  • France
    1997–2025
    #2,059
    in 2025
  • Canada
    2008–2024
    #468
    in 2024
  • South Australia
    2008–2013
    #754
    in 2013

Popularity data from Office for National Statistics, National Records of Scotland, Northern Ireland Statistics and Research Agency, Central Statistics Office, Institut national de la statistique et des études économiques, Statistics Canada and Consumer and Business Services (South Australia). ONS, NRS, NISRA data under Open Government Licence v3.0. CSO, CBS SA data under CC BY 4.0. INSEE data under Licence Ouverte / Etalab 2.0. StatCan data under Statistics Canada Open Licence.

Notable people named Cillian

People whose public names include Cillian, backed by Wikidata given-name records and ordered by linked Wikimedia pages. The name may be a middle name.

People data from Wikidata (CC0). Fame is measured, not judged — the order reflects how widely each person is documented, not the U.S. birth records popularity this page is otherwise about.

Cillian in other languages

Cross-language forms and variants of Cillian. Linked forms have their own page here.

Killian

Variant forms from Wikidata (CC0). Most are used mainly outside the United States; U.S. birth records statistics cover US usage only.

Cillian by the numbers

The raw record for each sex the name is used for.

As a boy's name

Rank in 2025
#507
Trend vs 5 yrs ago
Up 450
Best rank ever
#463
2024
Peak year
2024
668 that year
First recorded
1995
Last recorded
2025
All-time count
4,084
Count in 2025
595

As a girl's name

Rank in 2025
Unranked
Trend vs 5 yrs ago
—
Best rank ever
#13,840
2024
Peak year
2024
6 that year
First recorded
2024
Last recorded
2024
All-time count
6
Count in 2025
Under 5

Names similar to Cillian

Matched on shared beginnings and endings, similar length, and comparable popularity.

WillianCaspianFlorianDarrianFinnianCassianJullianBastianKylianJavianFavianJayvianKilianVivianDavianZavianKillianDemianTristianTavianXavianHadrianSabastianKrystian

Names with a curve like Cillian

Not spelling — timing. These names rose, peaked and faded in the same years as Cillian, so they read as being from the same moment even when they look nothing alike.

KrewZakaiTruReignLianCaspianMyloKenzoAnderEliamLedgerAzriel

Sibling names for Cillian

Names from the same era and popularity tier — the two things that make a sibling set feel deliberate — skipping lookalike spellings and shared initials.

Explore around Cillian

Top names of 2024, Cillian's peak yearThe 2020s in fullOther names that peaked in 2024Boys' names starting with CIrish NamesUnique Boy Names