(UNDERGOING MAJOR EDITING! Sorry!)
Prince Manor is the ancestral home of the Noble House of Prince, located in the Ulster Province of the County Down of Ireland, on sixty beautiful acres of land they call Cóis Dara, which include the Verdigris Marsh.
It's been their home for many generations, and each generation has added their magical skills to the manor's protection shield.
There are only two ways to cross the shield if you're not blood-related to the family, if you're holding the Prince family portkey or using side-along apparition with a family member. The portkey's kept in vault 886 at Gringotts.