Arms : Sable a Castle of five Towers in perspective in pentagon two two and one Or on a Chief dancetty of three points downward Argent as many Ravens close Sable.
Crest : On a Wreath Argent and Sable in front of a Crosier erect Or a Dragon passant Gules resting the dexter forefoot on a Garb or.
Supporters : On the dexter side a Boar Gules armed Or langued Azure charged on the shoulder with a Cross Sable fimbriated Or and on the sinister side a Welsh Mountain Ram proper charged on the shoulder with a Fountain.
Motto: 'DIOGEL DAN DDINEFWR' - Safe under Dinefwr
The arms were officially granted on October 1, 1976.
The Borough was named after Dinefwr or Dynevor Castle. This castle was the ancient seat of the Kings of Deheubarth. The main charge in the arms is therefore a castle. The castle has five towers and is pentagonal in shape to indicate the merging of five councils in the new Borough. The black field and indented edge to the chief indicate the presence of the Black Mountains in the area. The three ravens in chief are from the arms of the Rhys family of Dinefwr, descendants of the Kings of Deheubarth.
The crest is a Welsh dragon, supporting a garb for agriculture and standing in front of a gold crosier for Talley Abbey.
The dexter supporter is Y Twrch Trwyth (The Wild Boar), because legend has it that King Arthur and his Knights hunted Wild Boar in the Amman Valley. The boar is differenced by a cross from Ammanford's arms. This represents "Cross Inn", which was the name by which the Village was known before the District became urbanized. The sinister supporter is a Welsh mountain ram, for the hill farming of the uplands. The ram is differenced by a fountain, for the many lakes of the area.
The motto -DIOGEL DAN DDINEFWR- means Safe Under Dinefwr.
Literature : Image and information provided by Laurence Jones