The coat of arms of the county used on formal and ceremonial occasions was designed by the Office of the Chief Herald. The coat of arms was selected from two designs which were put on display and comments were invited from the general public.
The Irish Crown featured on the former Borough coat of arms - associations with King Laoghaire and Dún Laoghaire's origins.
Oak Branch with Acorns; to represent the ancient wooded nature of the entire county and the aspiration for conservation of its natural environment.
Shamrock; from the seal of Rathdown No.1 Rural District Council.
Viking Ship; featured on the former Borough coat of arms - represents the fact that the coastal area has Viking associations.
Mountain / Hill (triangle); represents the hills and part of the Dublin Mountains to the south and south-west of the county.
The Sea; represents the maritime tradition of the county and its importance for trade and recreation. It also represents the common coastline of the two former administrative areas unified by the Council.
Motto; Ó Chuan go Sliabh - from the harbour to the mountain.
Council logo; a simplified representation of the Dún Laoghaire-Rathdown
County Council identity, takes it’s inspiration from the Council Motto.