Namesakes
Declán of Ardmore
(m) ?-4xx 
Saints
Declan Costello
(m)
Fictional Characters from Television 1994 Heartbreak High
Declan Dunn
(m)
Fictional Characters from Television 2000 Mysterious Ways
Elvis Costello
(a.k.a. Declan) (m) 1954-
Notable Musicians
Rock and Roll Hall-of-Famers 2003 Elvis Costello & the Attractions