The official description of the R126 from the Roads Act 1993 (Classification of Regional Roads) Order 2012[1] reads:
R126: Lissenhall - Portrane, County Dublin
Between its junction with R132 at Lissenhall Great and its terminal point at the car park at Portraine via Hearse Road, Lanestown, Donabate, Bellalease and the Quay Road at Portraine all in the county of Fingal.