Dieppe, town and seaport, northern France, Seine-Maritime département, Haute-Normandie région, on the English Channel, north of Rouen and northwest of Paris. It stands at the mouth of the Arques River in a valley bordered on each side by steep white cliffs.
In the old town many houses date back to the early 18th century. The castle, built in 1435, was damaged in 1944 but has been restored and now houses a museum. Much of the town was rebuilt after World War II. Dieppe is the seaside resort closest to Paris; the pebbly beach with its marine promenade became fashionable in the 19th century. A casino is nearby.
The name Dieppe probably comes from the Saxon word deop (“deep”)—a reference to the depth of the estuary. The French kings, realizing the strategic importance of the town, granted it numerous privileges; when it was occupied by the English during the Hundred Years’ War, the inhabitants expelled them at the first opportunity, in 1435. Dieppe, mainly Protestant, suffered greatly during the Wars of Religion, but its darkest period came in the second part of the 17th century. In 1668 almost 10,000 of its people died during a plague; in 1685 the Protestants of the town were persecuted after the revocation of the Edict of Nantes; and in 1694 the town was almost completely destroyed by the English and Dutch fleets. The Allies landed in Dieppe in August 1942 and suffered serious losses in a test of German defenses near port facilities.
The port, cut in the bed of the Arques River, is one of the safest on the English Channel, but its shallowness hinders modern shipping. Cross-channel ferry traffic with Newhaven, Eng., has decreased as a result of competition from the Channel Tunnel. Although the fishing port is well placed to serve the Paris market, fishing activity has also declined. The commercial port handles only modest traffic; however, it specializes in the import of fruits, mainly from Africa. Many of the town’s traditional industries have disappeared, but attempts have been made to revive the economy through the attraction of small and medium-sized businesses. The Euro Channel business park was created to promote such development. Pop. (1999) 34,653; (2005 est.) 33,500.