The town was named after the castle built in the town named for Lord Blayney. He received the lands from James I after they were forfeited to Elizabeth I from the MacMahon chieftains during her reign. In modern times, the town has gained a reputation for being a musical centre for Ireland.
Concepta Riley was born in the town on 15th January 1926 and spent her formative years there, moving to Weatherfield in 1960 where she met and later married widower Harry Hewitt. The couple moved back to Castleblayney in 1964 when Concepta's father Sean Riley retired and Harry took over the running of his garage. Concepta continued to make visits back to her friends in Coronation Street until 1975. In July 1974 her step-daughter Lucille Hewitt also moved to Ireland to be with Concepta and her half-brother Christopher Hewitt.