The Seine below Vétheuil is a river in no hurry. It swings in long, lazy loops between chalk cliffs and poplar-lined banks, the water slow and green, and the road that follows it, the D913 on the north side, is one of the best easy rides in the Île-de-France. The Vexin plateau rises on one side, topped with fields and woodland, and the river flows below, with islands, barges and the occasional pleasure boat.
The chalk is the story. Over millions of years, the Seine has cut through the Cretaceous chalk, leaving white cliffs that glow in the sun, and in places the rock is riddled with caves. At Haute-Isle, a village a few kilometres downstream, people lived in houses dug into the cliff until recent times, and some are still used, their chimneys poking out of the rock face. At La Roche-Guyon, a little further, a castle with a medieval keep carved into the cliff and a later house at its foot stands above the road. In 1944, Field Marshal Rommel made it his headquarters, during the defence of Normandy, and the underground passages that served his staff are still there.
Behind these cliffs, the villages of the Vexin, Freneuse and Gasny, have a quiet, rural air, with stone houses, churches and fields of wheat and rapeseed. The Vexin français regional park protects the plateau, and cyclists and walkers are a common sight on the riverside lanes. Limay, across from Mantes, is the nearest sizeable town, with about eighteen and a half thousand people.
The riding along the river is a series of easy curves, with the cliffs on one side and the water on the other, and a surface that is generally good. In the evening, the cliffs glow gold and the river turns to silver, and it is the best time to go. Mist on cold mornings can linger on the water, and the road under the cliffs is damp and sometimes slippery. Be careful of falling stones in winter, when frost splits the chalk, and watch for cyclists on summer weekends.
Fuel and shops are in Limay and Mantes, so fill up there before heading along the river. The smell of river water, damp stone and wild garlic in spring is pleasant company, and the whole stretch is a calm, quiet end to a day.