St. Philip's Castle was a fortress guarding the entrance to the port of Mahón

Mahon

Mahón is a municipality and the capital city of the Balearic Island of Minorca , located in the eastern part of the island. Mahon has the second deepest natural harbor in the world: 5 km long and up to 900m. wide...

. It is located in the municipality

Municipality

A municipality is essentially an urban administrative division having corporate status and usually powers of self-government. It can also be used to mean the governing body of a municipality. A municipality is a general-purpose administrative subdivision, as opposed to a special-purpose district...

 of Es Castell

Es Castell

Es Castell is a small municipality in eastern Minorca in the Balearic Islands, Spain. The town was founded in 1771 by British Col. Patrick Mackellar and was originally called Georgetown in honour of King George III, however it takes its current name from the large fort nearby, known to the British...

, on the island of Minorca

Minorca

Min Orca or Menorca is one of the Balearic Islands located in the Mediterranean Sea belonging to Spain. It takes its name from being smaller than the nearby island of Majorca....

.

It was rebuilt by British forces in the 1760s, around an earlier Spanish

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 fort, the Castell de San Felipe, which had been established about 1554. It is best known for its unsuccessful defence on two occasions by the British: during the Battle of Minorca

Battle of Minorca

The Battle of Minorca was a naval battle between French and British fleets. It was the opening sea battle of the Seven Years' War in the European theatre. Shortly after Great Britain declared war on the House of Bourbon, their squadrons met off the Mediterranean island of Minorca. The fight...

 in 1756 and the Invasion of Minorca, 1781

Invasion of Minorca, 1781

The Franco-Spanish conquest of Minorca from its British defenders in February 1782, after the Siege of Fort St. Philip lasting over five months, was an important step in the achievement of Spain's aims in its alliance with France against Britain during the American War of Independence...

. Following the latter event, the castle was partly demolished.