The Presidential Museum (Presidential Museum), also known as Fort Christiansborg or simply the Castle, is a castle located in Osu, Accra, Ghana on the coast of the Atlantic Ocean's Gulf of Guinea. The first substantial fort was built by Denmark-Norway in the 1660s, though the castle has changed hands between Denmark-Norway, Portugal, the Akwamu, Britain, and finally post-Independence Ghana, and was rebuilt numerous times. The castle become the house of government when the capital of Gold Coast (now Ghana) was moved from Cape Coast to Accra in 1877.

For most of the castle's history, it has been the seat of government in Ghana with some interruptions, the latest when the John Kufuor administration moved the seat of government to Golden Jubilee House after 6 January 2009, which was quickly reversed by the incoming John Atta Mills administration. It also serves as the place where the late president of Ghana John Atta Mills was buried, in a bird sanctuary, overlooking the Atlantic Ocean. The castle has now been converted into a presidential museum (museum of heads of state) in commemoration of Ghana's 60th independence day celebrations in 2017.