Magellan Castle (マゼラン・キャッスル) orbited the planet Venus, and in the manga and Crystal it was the palace of Princess Venus, given to her by Queen Serenity when she was born. Sailor Venus described the castle as being surrounded by sulfur fog. According to Artemis, it floated over the land of Aphrodite.
In Act 48 of the manga and Sailor Moon Eternal, the Solar System Senshi called upon the power of their castles and directed it to the Holy Grail, which gave Sailor Moon the power to transform into Eternal Sailor Moon. In Chapters 1 and 15 of the Codename: Sailor V manga, the palace was shown as Minako was told of and remembered her past life.
- Magellan Castle's name is derived from the name of a space probe sent to explore Venus in the 1990s.
- In the Sailor Moon Eternal visual book, its name was written as マゼンダ・キャッスル (mazenda kyassuru) instead of マゼラン・キャッスル (mazeran kyassuru).