The Federative Republic of Brazil is a union of twenty-seven Federative Units (Portuguese: Unidades Federativas (UF)): twenty-six states (estados; singular estado) and one federal district (Distrito Federal), where is located the federal capital, Brasília. The states are generally based on historical, conventional borders which have developed over time. The federal district is not a state in its own right, but shares some characteristics of a state and some of a municipality. The Federal District is bordered by the states of Goiás and Minas Gerais. The codes given below are defined in ISO 3166-2:BR.

The first administrative divisions of Brazil were the hereditary captaincies (capitanias hereditárias), stretches of land leased to Portuguese noblemen or merchants with a charter to colonize the land. The captaincies were to be passed from father to son, but the crown retained the power of revoking it, which the king indeed did in the 16th century. Then the vast Portuguese dominion in South America was divided between the State of Brazil, in the southern half, and the State of Maranhão, in the northern half (note that Maranhão by then referred not only to current Maranhão, but rather to the whole of the Amazon region; the name marã-nã in old Tupi language means "wide river", i.e. the Amazon River).

Brazil ⁱ/brəˈzɪl/ (Portuguese: Brasil, IPA: [bɾaˈziw]), officially the Federative Republic of Brazil (Portuguese: República Federativa do Brasil,  listen (help·info)), is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people. It is the only Portuguese-speaking country in the Americas and the largest lusophone country in the world.

Bounded by the Atlantic Ocean on the east, Brazil has a coastline of 7,491 km (4,655 mi). It is bordered on the north by Venezuela, Guyana, Suriname and the French overseas region of French Guiana; on the northwest by Colombia; on the west by Bolivia and Peru; on the southwest by Argentina and Paraguay and on the south by Uruguay. Numerous archipelagos form part of Brazilian territory, such as Fernando de Noronha, Rocas Atoll, Saint Peter and Paul Rocks, and Trindade and Martim Vaz. It borders all other South American countries except Ecuador and Chile.

Brazil was a colony of Portugal from the landing of Pedro Álvares Cabral in 1500 until 1815, when it was elevated to the rank of kingdom and the United Kingdom of Portugal, Brazil and the Algarves was formed. The colonial bond was in fact broken in 1808, when the capital of the Portuguese colonial empire was transferred from Lisbon to Rio de Janeiro, after Napoleon invaded Portugal.Independence was achieved in 1822 with the formation of the Empire of Brazil, a unitary state governed under a constitutional monarchy and a parliamentary system. The country became a presidential republic in 1889, when a military coup d'état proclaimed the Republic, although the bicameral legislature, now called Congress, dates back to the ratification of the first constitution in 1824. Its current Constitution, formulated in 1988, defines Brazil as a Federal Republic. The Federation is formed by the union of the Federal District, the 26 States, and the 5,564 Municipalities.