Fort Hammenhiel (Sinhalese: හැමන්හිල් බලකොටුව; Tamil: அம்மன்னீல் கோட்டை) is a fort built around a small island between the islands of Kayts and Karaitivu of Jaffna Peninsula in Northern Sri Lanka. The Portuguese built this fort in the mid 17th century of quarried coral and named it Fortaleza Real (Fort Royal). The Dutch renamed it as Hammenhiel (Heel of the Ham) and it was rebuilt by them in 1680. The prison has nine large dungeons to store gunpowder.