Antofagasta is a port city in northern Chile, about 1,100 kilometres north of Santiago. It is the capital of Antofagasta Province and Antofagasta R…Antofagasta is a port city in northern Chile, about 1,100 kilometres north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669.