Declan is an ancient Irish given name anglicized form of an Irish Gaelic saint's name Declán, also Deaglán or Déaglán, or, in colloquial terms, Det, normally all capitalised when written. St. Declan founded a monestary in Ireland in the 5th century, and the St. Declan's stone has been credited as the site of many miracles. The name is believed to mean "man of prayer" or "full of goodness".
Those bearing it include:
Saint Declán of Ardmore (fl. 5th century)
Declan Affley (1939–1985), Australian folk singer and musician
Declan Bree (born 1951), Irish politician and social campaigner
Declan Costello (born 1926), Attorney General of Ireland
Declan Coyne, a fictional character in Degrassi: The Next Generation
Declan Curry (fl. since 1997), Irish journalist who works for BBC News and BBC Breakfast in the United Kingdom
Declan de Barra (born c. 1960), Irish musician, vocalist and bodhrán player of the former band Clann Zú
Declan Donnellan (born 1953), British theatre director
Declan Donnelly (born 1975), one half of British television duo Ant and Dec
Declan Galbraith (born 1991), English singer
Declan Ganley (born 1968), Irish businessman and political activist
Declan Kidney (born 1959), Irish rugby union coach
Declan McCullagh, journalist
Declan McGonagle, Irish art curator
Declan McKenna (born 1998), British singer, songwriter, and musician
Declan Patrick Aloysius MacManus (born 1954), the birth name of British musician Elvis Costello
Declan Meehan (radio presenter), Irish radio presenter
Declan Meehan (Gaelic footballer), Irish Gaelic footballer
Declan Nerney (born c. 1970), Irish country music personality
Declan O'Rourke (born 1976), Irish Singer/Songwriter
Declan O'Sullivan, Irish Gaelic footballer
Declan Quinn (born 1957), American cinematographer
Declan Ryan (born 1968), Irish sportsman
Declan Sinnott (born c. 1950), Irish musician
