Semarang, city and port, southern Indonesia, on the island of Java, capital of Central Java Province. On the Java Sea, at the mouth of the Semarang River, Semarang is a major seaport and commercial center for central Java, with an excellent harbor. The city contains shipyards, railroad workshops, and industries in which machinery, electrical equipment, shoes, textiles, and glass are manufactured. Semarang's principal exports are sugar, copra, tobacco, coffee, and rubber. Population (1997 estimate) 812,979.