Cap Hornu is the headland just west of St-Valéry, where the wooded chalk cliff falls away to the open mouth of the bay. The point can be reached on foot in half an hour from the upper town by following the GR125 coastal path, or by a short drive out along the D940. A hotel and restaurant occupy the headland, and there is a small parking area where the path begins.
From the cliff edge you have an uninterrupted view across the estuary toward Le Crotoy, the saltings, and the open Channel. This is one of the best places near St-Valéry to watch the tide come in or out — twice a day the water races over the flats at a walking pace. The footpath continues westward toward Hourdel and Cayeux for those wanting a longer walk.