Cillian is one of the native Irish names that, along with Aiden and Declan, is becoming an unlikely favorite in contemporary America. The Killian spelling has been more popular in the US, but Cillian's star is rising, perhaps thanks to Irish actor Cillian Murphy, star of Oppenheimer and Peaky Blinders.

Casey is a name with a big wide grin, Irish, friendly, and open, and associated with several American folk heroes--Casey Jones, the engine driver of the Cannonball Express who gave his life to save his passengers, and the legendary Casey at the Bat.

Thanks to its dashing Anglo-Irish image — due partly to Colins Firth and Farrell — and its C-initialed two-syllable sound, Colin and its cousin Collin have enjoyed a long run of popularity, reaching as high as Number 84 in 2004.

Connor, the appealing name of an early semi-legendary king of Ulster in Irish mythology, sits firmly in the Top 100 and taken together with its alternate spellings would rank even higher. In its native Ireland the Conor version is one of the highest charting boys’ name.

Carson is one of the most long-running popular androgynous baby names, with a dash of the Wild West via the legendary Missouri frontiersman Kit Carson. Dating back to when it was the name of Nancy Drew's Dad, Carson is still steadily in the Top 200 baby names.

Has fallen off its Kathie Lee Gifford inspired peak in the 1990s, but since that notably celebrity baby is now a grownup and out of the limelight, Cassidy may once again reclaim its own Irish charm.

Collins is a surname name that has made the girls' Top 1000 thanks to its use for the daughter of the real-life Blind Side heroine. As of 2022, Collins climbed into the US Top 300. This derivation of the Greek Nicholas—which means "people of victory"—or the Irish and Scottish Colin—which may itself be a Nicholas derivation or an Anglicization of the word for pup—has a stylish feel made more so by that final s.

Callahan, the simpler spelling of Callaghan, is a rhythmic jig of a name whose history harks back to the ancient King of Munster. In the Dirty Harry movies, the Clint Eastwood character is Harry Callahan.

A handsome Irish name for boys, very popular in that country, but in the US this traditional spelling might cause pronunciation problems. Still, whether Cian or Kian, it's simple and straightforward enough for the initiated. Cian is rising in the British popularity charts.

Both offbeat and upbeat, this evocative traditional Irish name that runs through Celtic mythology is known here via award-winning novelist Cormac McCarthy (born Charles). The author's adopted name is related to Cormac Mac Airt, one of the great legendary high kings of Ireland.

Former teen idol name, now middle-aged. This name has been on a steady decline since the early-1990s.

A popular choice in Ireland, Clodagh was the name of a river and later a saint. The "cloddy" aspect of the name has prevented it from spreading beyond Ireland, but that could change with the rise of other Irish choices like Maeve and Orla.

An Irish and Welsh form of Catherine, Caitlin was a boom name of the eighties, rocketing from obscurity (Americans first heard it via the wife of doomed poet Dylan Thomas) to the height of popularity in the space of a decade. The original name was gradually eclipsed by its myriad spelling variations -- Katelyn and Kaitlyn both soon topping it on the popularity lists.

One of the original unisex Irish surname names, energetic Casey bounced onto the scene in the 1960s, then peaked in the 1980s for both boys and girls. Today Casey is having a resurgence for both girls and boys and re-entered the charts on the girls' side, likely due to the character Kayce Dutton (pronounced like Casey) on the hit show Yellowstone.

Cael is the name of the angel of the zodiac sign of Cancer and also of a warrior of Irish mythology. Its ascendance to the Top 1000 over the past decade probably has to do with its similarity to Cale and Kale (and Kyle and Cayden etcetera).

Crosby is an attractively laid-back Irish surname with retro musical associations to Bing and Crosby, Stills, and Nash, and with a jaunty air. Crosby Braverman was the name of a character on the TV show Parenthood, played by Dax Shepard.

Thanks to its dashing British image and c-initialed two-syllable sound, Colin/Collin has enjoyed a long run of popularity.

Extremely popular in Ireland, Ciaran is also well used in England and is beginning to be adopted by parents in the U.S., though usually via the more American-friendly Kieran spelling. The Irish spelling is, however, becoming more familiar on this side of the Atlantic, due to the rising popularity of Belfast-born actor Ciaran Hinds.

A variation of Corey, this spelling has also been on a steady decline since the early-1990s. Its days are likely numbered on the US popularity charts altogether.

Colm is a popular Irish name for boys that could immigrate, especially with its peaceful meaning. Colm Toibin is a contemporary Irish novelist and critic, author of The Master and Brooklyn; Colm Meaney is an Irish actor. Pronunciation is two syllables instead of one, like Colin with an 'm' at the end. Colm is related to Columba, Colom, Colum, Callum, and Malcolm.