The Castle, Government building in Jamestown, Saint Helena.

The Castle is a Grade I-listed government complex in Jamestown, Saint Helena, with its oldest parts dating to 1708 and largely rebuilt in the 1860s after termite damage. It has a modest, castle-like appearance and includes the Legislative Council Chamber on the second floor, the Governor's office, the Printing Office, Savings Bank and the colony's archives.

Governor John Roberts ordered the Castle built in 1708 on the site of the triangular James Fort, replacing the decrepit Fort House as the governor's residence and housing the island's administrative offices. An upper storey was added in 1776, and the building was largely rebuilt in 1867 to repair termite damage. The German source dates parts of the complex to 1659 and the renovation to 1860.

The Castle houses the Legislative Council, which meets in the Council Chamber on the second floor, and the Governor's office, though the governor has lived at Plantation House since 1792. The complex also holds the colony's archives, the Printing Office and a savings bank. Only the foyer is open to the public.

Only the foyer of the Castle is open to the public; the rest of the complex houses government offices, the Legislative Council chamber, the police headquarters, a library and the supreme court. Visitors should plan to see the exterior and the entrance hall, as access beyond the foyer is not permitted.

The Castle's name is misleading: it never was a castle, but part of the East India Company's fortifications guarding the seaward mouth of James Valley. The complex also houses the Printing Office, the Savings Bank and the colony's archives, and only its foyer is open to the public.