rio's favelas are mostly set in the zona norte and in the zona oeste of the city - favelas in rio are also referred to as 'morros,'  meaning 'hills,' since many of them are built on hillsides -  the preferred term for favela is 'comunidade' (community).

in rio, favelas started to grow significantly in the 1940's, as a result of a housing crisis that drove many cariocas to move into undeveloped urban areas.      

later, favelas grew even faster during the economic boom of the 1970's, when migrant workers from many parts of brazil moved in search of employment and prosperity - statistics show that favelas are growing at about twice the rate of other neighborhoods in rio- we provide links to statistics here.

currently, there are hundreds of favelas in rio de janeiro, home to an estimated one million people or around 20% of rio's population.