Callan is an ancient Irish surname and given name, derived from the Gaelic 'Ceallán'. It means 'devoted to St. John', reflecting its origin as a patronymic, passed down through generations of descendants of a man named Seán or John. The name gained prominence among the Irish nobility in the 12th century, with notable bearers including Callan of Otty, who was an ancestor of the O'Briens, the Kings of Thomond.
The name Callan experienced significant growth in popularity from the mid-80s to the late 90s, peaking with 50 births in 1988 and remaining quite common until around 2004. After that point, its usage began to decline steadily, falling below 30 births per year consistently since 2010, except for a brief resurgence in recent years (45 births in 2018, 52 in 2021, and 59 in 2023). Overall, the name Callan has seen a total of 1,350 births from 1982 to 2023.