Ischia is a
volcanic island in the
Tyrrhenian Sea. It lies at the northern end of the
Gulf of Naples, about from the city of
Naples. It is the largest of the
Phlegrean Islands. Roughly trapezoidal, it measures approximately east to west and north to south and has about of coastline and a surface area of . It is almost entirely mountainous, the highest peak being
Mount Epomeo at . The island has a population of over 60,000 people.