Hillsborough Castle is a historic mansion located in Hillsborough, Northern Ireland. It serves as the official residence of the Secretary of State for Northern Ireland and is surrounded by beautiful gardens that are open to the public. The castle has a rich history, dating back to the 18th century, and has been a site for many important political events. The architecture of Hillsborough Castle reflects a mix of styles, including Georgian and Victorian influences. Visitors can explore the stunning grounds, which feature ornamental gardens, woodlands, and a lake. The castle also hosts various events and exhibitions throughout the year, showcasing its cultural significance.