The European route E 03, is a series of road in Europe, part of the United Nations International E-road network, running from Cherbourg, France to La Rochelle, also in France.
The road is 459 km (285 mi) long, and travels along the French routes nationales. From Cherbourg to Carentan, it travels along the Route nationale 13. At Carentan, it changes to the RN 174. It then moves onto the autoroute, mainly the A84 (which it joins at Junction 40) until it reaches Saint-Lô at Junction 16. It then rejoins the RN, mainly RN 136 at Rennes before finally travelling along the Route nationale 137 to its final destination of La Rochelle. It also comes close to the outskirts of Nantes.