The Tietê River is a Brazilian river in the state of São Paulo.

São Paulo is one of the 26 states of the Federative Republic of Brazil and is named after Saint Paul of Tarsus. It is located in the Southeast Region and is limited by the states of Minas Gerais to the north and northeast, Paraná to the south, Rio de Janeiro to the east and Mato Grosso do Sul to the west, in addition to the Atlantic Ocean to the southeast. It is divided into 645 municipalities and its total area is 248,219.481 square kilometres km², which is equivalent to 2.9% of Brazil's surface, being slightly larger than the United Kingdom. Its capital is the municipality of São Paulo.