The city and Volkswagen factory were captured on April 11, 1945 by US troops and about 7,700 forced labourers were liberated from the Volkswagen factory. The US troops occupied the city until the end of June, during which time the city was renamed Wolfsburg on 25 May 1945, after the eponymous castle located there. The American occupation ended at the end of June 1945 when the region became part of the British occupation zone. In 1951, Wolfsburg was separated from the District of Gifhorn, and became an urban district.