Arauco Province is one of four provinces of the Chilean region of Bío Bío (VIII). It spans a coastal area of just south of the mouth of the Biobío River, the traditional demarcation between the nation's major natural regions, Zona Central and Zona Sur. The province originally covered the once-independent indigenous territory of Araucanía, but this was afterward divided into four provinces. It is devoted largely to agricultural pursuits. The capital Lebu (population 25,000) is situated on the coast about south of Concepción with which it is connected by rail.