The Royal Arsenal, Woolwich is an establishment on the south bank of the River Thames in Woolwich in south-east London, England, that was used for the manufacture of armaments and ammunition, proofing, and explosives research for the British armed forces. It was originally known as the Woolwich Warren, having begun on land previously used as a domestic warren in the grounds of a mid-16th century Tudor house, Tower Place. Much of the initial history of the site is linked with that of the Office of Ordnance, which purchased the Warren in the late 17th century in order to expand an earlier base at Gun Wharf in Woolwich Dockyard.
Over the next two centuries, as operations grew and innovations were pursued, the site expanded massively. At the time of the First World War the Arsenal covered 1,285 acres (520 ha) and employed close to 80,000 people. Thereafter its operations were scaled down. It finally closed as a factory in 1967 and the Ministry of Defence moved out in 1994. Today the area, so long a secret enclave, is open to the public and is being redeveloped for housing and community use.