Melilli stands at about 310 metres (1,020 ft) above sea level close to the Monti Climiti chain, overlooking the Megara bay and the industrial district of Augusta-Priolo.

Its strategic situation between the major cities of Augusta and Syracuse has played a critical role in its growth.

The Chiesa Madre San Nicolò Vescovo (Mother Church of St Nicolas, Bishop of Myra), dedicated to Saint Nicholas, has a ceiling painted with the Triumph of the Faith by Olivo Sozzi.

The church of San Sebastiano, dating from the 18th century, houses various paintings by Sozzi, among which are a Coronation of Saint Sebastian and The Triumph of the Faith, and a marble altarpiece representing the Deposition of St. Bartholomew.

The neighboring salt-mines of Augusta were an important economic resource as far as the end of World War II.