Rio de Janeiro ( River of January) is one of the 27 federative units of Brazil. It has the second largest economy of Brazil, with the largest being that of the state of São Paulo.
The state of Rio de Janeiro is located within the Brazilian geopolitical region classified as the Southeast (assigned by IBGE). Rio de Janeiro shares borders with all the other states in the same Southeast macroregion: Minas Gerais (N and NW), Espírito Santo (NE) and São Paulo (SW). It is bounded on the east and south by the South Atlantic Ocean. Rio de Janeiro has an area of. Its capital is the city of Rio de Janeiro, which was the capital of the Portuguese Colony of Brazil from 1763 to 1815, of the following United Kingdom of Portugal, Brazil and the Algarves from 1815 to 1822, and of later independent Brazil as a kingdom and republic from 1822 to 1960.
The state's 22 largest cities are Rio de Janeiro, São Gonçalo, Duque de Caxias, Nova Iguaçu, Niterói, Campos dos Goytacazes, Belford Roxo, São João de Meriti, Petrópolis, Volta Redonda, Magé, Macaé, Itaboraí, Cabo Frio, Armação dos Búzios, Angra dos Reis, Nova Friburgo, Barra Mansa, Barra do Piraí, Teresópolis, Mesquita and Nilópolis.
Rio de Janeiro is the smallest state in the Southeast macroregion and one of the smallest in Brazil. It is, however, the third most populous Brazilian state, with a population of 16 million of people in 2011 (making it the most densely populated state in Brazil) and has the third longest coastline in the country (after those of the states of Bahia and Maranhão).
In the Brazilian flag, the state is represented by Mimosa, the beta star in the Southern Cross (β Cru).
The original demonym for the State of Rio de Janeiro is "fluminense", from Latin flumen, fluminis, meaning "river". While "carioca" (from Old Tupi) is an older term, first attested in 1502, "fluminense" was sanctioned in 1783, a few years after the city had become the capital of the Brazilian colonies, as the official demonym of the Royal Captaincy of Rio de Janeiro and subsequently of the Province of Rio de Janeiro. From 1783 through the Imperial Regime, "carioca" remained an unofficial term which other Brazilians used for the inhabitants of the city as well as the province. During the first years of the Brazilian Republic, "carioca" came to be the name given to those who lived in the city's slums or a pejorative used to refer to the bureaucratic elite of the Federal District. Only when the city lost its status as Federal District (to Brasília) and became the State of Guanabara in 1960 did "carioca" become an official demonym along with "guanabarino". In 1975, Guanabara State was incorporated into Rio de Janeiro State, becoming the present City of Rio de Janeiro. "Carioca" became the demonym of the city, while fluminense continues to be used for the state as a whole.
Although "carioca" officially refers only to the city, the term is commonly used to refer to the entire state. Contemporary social movements like "Somos Todos Cariocas" ("We are all Cariocas") have tried to achieve the official recognition of "carioca" as a co-official demonym of the state.