The RN 15 originates at junction 14 on the A13 autoroute in the Yvelines département near Bonnières-sur-Seine.

The RN 15 straightens and leaves the river, passing the town of Gaillon.

The road runs parallel to the A13 autoroute and passes through the Forêt de Louviers heading North and over the river at Pont-de-l'Arche onto the right bank of the Seine.

The road follows the river bank overlooked by surrounding cliffs including the Roches de Saint-Adrien.

The road meets the Route nationale 14 and enters the capital of Normandy, Rouen.