CHILLAN, a province and town in the south of Chile. The province is fifty-five miles long from east to west, and forty broad from north to south, and contains about 2200 square miles of superficies. It extends from the summit of the Andes on the east, to the province of Itata, which separates it from the Pacific Ocean. It is watered by a number of streams, the Nuble, Cato, Chillan, Dinguilin, Danielquin, and Guillayo, which flow from the Cordillera, and unite to form the Itata river. It is a small but very fertile province, consisting of mountain ranges to the east, and beautiful and well-watered plains and valleys to the west. The town of Chillan was built on the margin of the same river, but it has been frequently inundated by the water of the Chillan, and it was levelled with the dust by an earthquake in 1751, but subsequently rebuilt in its present situation. Before the revolution, the town and province were more populous than at present, as the revolutionary war and frequent incursions of the unsubdued Araucanian Indians have greatly diminished the extent of cultivation and the number of inhabitants in the province. Its present population may be estimated at 30,000.