The official definition of the R828 from the Roads Act 1993 (Classification of Regional Roads) Order 2012 states:[2]
R828: Stradbrook Road - Killiney, County Dublin
Between its junction with R827 at Deansgrange Road and its junction with R118 at Church Road Killiney via Stradbrook Road, Abbey Road and Rochestown Avenue all in the county of Dún Laoghaire–Rathdown.