Princess Anne's Battery is an artillery battery in the British Overseas Territory of Gibraltar. It is located on Willis's Plateau at the northern end of the Upper Rock Nature Reserve, above Princess Caroline's Battery. It was named after Anne, Princess Royal and Princess of Orange, the eldest daughter of George II. However, its name is often confused with those of other batteries in the area. In 1732, guns were first mounted on the battery, which also saw action during the Great Siege of Gibraltar. Princess Anne's Battery was updated in the nineteenth and twentieth centuries, with the latter modernisation entailing the installation of four QF 5.25 inch guns with both anti-aircraft and coastal defence capabilities. The battery was manned into the early 1980s, after which it was decommission