Killiney Hill () is the southernmost of the two hills which form the southern boundary of Dublin Bay (the other being Dalkey Hill). Crowned by an obelisk, the hill is 153 metres high and has views over the surrounding areas: Dublin to the northwest; the Irish Sea and the mountains of Wales (on a clear day) to the east and southeast; and Bray Head and the Wicklow Mountains to the south. The hill was higher in the past but material was removed from the summit for the construction of the pier at Dún Laoghaire.