Mejillones is a Chilean port city and commune in Antofagasta Province in the Antofagasta Region. Its name is the plural form of the Spanish mejillón meaning "mussel", referring to a particularly abundant species and preferred staple food of its indigenous inhabitants. It is situated in the northern side of the Mejillones Peninsula, 60 km north of the city of Antofagasta. To the west, in the northern part of peninsula, is Punta de Angamos, the site of the naval combat of the same name, fought during the War of the Pacific (1879-1883).
Mejillones is surrounded by the waters of the Pacific Ocean to the west and by one of the most arid deserts in the world to the east, the Atacama. It also marks the country's widest point along a parallel (362 km).