Nisida is a volcanic islet of the Flegrean Islands archipelago, in southern Italy. It lies at a very short distance from Cape Posillipo, just north of Naples; it is now connected to the mainland by a stone bridge. The islet is almost circular, with a flooded crater forming the bay of Porto Paone on the southwest coast. It has a diameter of about 0.5 kilometres (0.3 miles) and a highest altitude of 105 metres (344 feet).

Isle of Nisida in the Gulf of Naples.

The name of the island comes from the Greek for "islet" (small island), νησίς, for which the accusative was nesida.[1]