Portugal is a country in southwestern Europe on the Iberian Peninsula. The Atlantic archipelagos of Azores and Madeira are part of Portugal and occupy strategic locations along western routes to the Strait of Gibraltar. Portugal is bordered by Spain and the Atlantic Ocean. The geography is mountainous north of the Tagus River. The government system is a republic; the chief of state is the president, and the head of government is the prime minister. Portugal has a service-based mixed economy in which the government has privatized many state-controlled firms and liberalized areas of the economy. Portugal is a member of the European Union (EU).