Wilhelmshaven (vɪlhɛlmsˈhaːfn̩, Wilhelm's Harbour; Northern Low Saxon: Willemshaven) is a coastal town in Lower Saxony, Germany. It is situated on the western side of the Jade Bight, a bay of the North Sea, and has a population of 76,089. Wilhelmshaven is the centre of the "Jade Bay" business region (which has around 330,000 inhabitants) and is Germany's main military port.
The adjacent Lower Saxony Wadden Sea National Park (part of the Wattenmeer UNESCO World Natural Heritage Site) provides the basis for the major tourism industry in the region.
The Siebethsburg castle, built before 1383, operated as a pirate stronghold; the Hanseatic League destroyed it in 1433. Four centuries later, the Kingdom of Prussia planned a fleet and a harbour on the North Sea. In 1853, Prince Adalbert of Prussia, a cousin of the Prussian King Frederick William IV, arranged the Jade Treaty (Jade-Vertrag) with the Grand Duchy of Oldenburg, in which Prussia and the Grand Duchy entered into a contract whereby Oldenburg ceded of its territory at the Jade Bight to Prussia. In 1869 King William I of Prussia (later also German Emperor) founded the town as an exclave of the Province of Hanover and a naval base for Prussia's developing fleet. All the hinterland of the city remained a part of Oldenburg.
A shipbuilding yard developed at Wilhelmshaven, the Kaiserliche Werft Wilhelmshaven (Wilhelmshaven Imperial Shipyard). On 30 June 1934 the "pocket battleship" Admiral Graf Spee was launched at Wilhelmshaven.
In 1937 Wilhelmshaven and the adjacent village Rüstringen merged and the united city, named Wilhelmshaven, became a part of the Free State of Oldenburg.
Bombing of Wilhelmshaven in World War II
In World War II (1939–1945), Allied bombing destroyed two thirds of the town's buildings while the main target, the Naval Shipyard Wilhelmshaven, remained operational despite serious damage. A major attack on residential areas of Wilhelmshaven was carried out on 15 October 1944. Various churches, hospitals, schools and many residential buildings were destroyed or severely damaged.