Palau is an island nation in the Pacific Ocean southeast of the Philippines. It is the westernmost archipelago in the Caroline chain, consisting of six island groups totaling more than 300 islands. The geology is varied from mountains on the main island to low, coral islands fringed by barrier reefs. The government system is a presidential republic in free association with the United States; the chief of state and the head of government is the president. Palau, largely dependent on the United States, has a traditional economic system in which the majority of the population engages in subsistence agriculture and farming.