▁name ▁in ▁Irish ▁and ▁English . ▁ ▁The ▁Dublin ▁system ▁had ▁ 2 2 ▁districts ▁— ▁Dublin ▁ 1 , ▁ 2 , ▁ 3 , ▁ 4 , ▁ 5 , ▁ 6 , ▁ 6 W , ▁ 7 , ▁ 8 , ▁ 9 , ▁ 1 0 , ▁ 1 1 , ▁ 1 2 , ▁ 1 3 , ▁ 1 4 , ▁ 1 5 , ▁ 1 6 , ▁ 1 7 , ▁ 1 8 , ▁ 2 0 , ▁ 2 2 , ▁ 2 4 . ▁These ▁were ▁incorpor ated ▁into ▁the ▁routing ▁keys ▁used ▁by ▁the ▁E ir code ▁national ▁post code ▁system ▁as ▁D 0 1 , ▁D 0 2 , ▁D 1 2 , ▁D 2 2 , ▁etc . ▁ ▁C ork ▁ ▁The ▁city ▁of ▁C ork ▁had ▁four ▁number ed ▁postal ▁districts , ▁but ▁these ▁were ▁used ▁internally ▁by ▁An ▁Post ▁and ▁rarely ▁on ▁mail . ▁C ork ▁ 1 ▁covered ▁the ▁city ▁centre ▁and ▁large ▁parts ▁of ▁the ▁surrounding ▁city , ▁e . g .: ▁the ▁" P atr ick ▁Street " ▁() ▁sign ▁displays ▁the ▁digit ▁' 1 '. ▁C ork ▁ 2 , ▁admin ister ed ▁from ▁the ▁Ball in l ough ▁sorting ▁office , ▁covered ▁the ▁south - east , ▁C ork ▁ 3 ▁( from ▁G ur ran ab ra her ) ▁covered ▁the ▁north - west ▁while ▁C ork ▁ 4 ▁( from ▁T og her ▁sorting ▁office ) ▁covered ▁the