The Northeast Region of Brazil is the third largest of five geopolitical regions of the country, composed of nine of its twenty-six states: Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Bahia, and the Fernando de Noronha Archipelago. It stretches from the Atlantic seaboard in the northeast and southeast, northwest and west to the Amazon Basin and south through the Espinhaço highlands in southern Bahia. It encloses the São Francisco River and drainage basin, important for the exploration, settlement and economic development of the region. The northeast was the first region to be discovered and colonized by European (principally Portuguese, Spanish and Dutch) explorers in the 16th century. The Northeast Region represents 18% of Brazilian territory, has a population of 53.6 million people, 28% of the total population of the country, and contributes 13.4% (2011) of Brazil's GDP. Nearly three quarters of the population lives in urban areas clustered along the Atlantic coast and about 15 million people live in the hinterland.