Cartagena is a Spanish city and a major naval station on the Mediterranean coast, south-eastern Iberia. As of January 2018, it ha…Cartagena is a Spanish city and a major naval station on the Mediterranean coast, south-eastern Iberia. As of January 2018, it has a population of 218,943 inhabitants. This makes Cartagena Murcia's second-largest municipality and Spain's sixth-largest city that is not a provincial-capital. The wider urban or metropolitan area of Cartagena, known as Campo de Cartagena, has a population of 409,586 inhabitants.