The B119 is a short loop off the A2 to serve the coastal village of Castlerock. It was originally unclassified but gained its number in the mid-1920s.
The road starts on the A2 to the west of Articlave and heads north along Sea Road. As we enter Castlerock the sea becomes visible ahead and we descend past houses to reach a mini-roundabout. Ahead, beyond the level crossing on the Belfast to Derry Line, lies the village centre and the sea front; however, we turn left. The 1926 OSNI Road Map suggests that the B119 headed through the village centre before following the coast back to the A2 but there is no road in that direction. It does seem likely, however, that the original route of the B119 crossed the railway by the station that still exists before following either Main Street or the Promenade then recrossing the railway line at a level crossing that is no longer open to traffic.
We follow Castle Walk Mews past a recreation ground before bearing left again into Freehall Road, which we now follow southwards. We soon enter open country. The National Trust's Downhill Estate lies to the right; the ruined Downhill House and clifftop Mussenden Temple are visible. We climb away from the coast and soon return to the A2 less than half a mile away from where we left it.