Uarini is a municipality in the Brazilian state of Amazonas, located in the country's Amazon region. It is one of the many municipalities that make up this vast northern state, which is Brazil's largest by area and is dominated by the Amazon rainforest and its river system.
According to estimates from the Brazilian Institute of Geography and Statistics (IBGE), Uarini had a population of 13,690 inhabitants in 2020. The municipality covers an area of 10,246 square kilometres, giving it a very low population density typical of much of the Amazonas interior.
Like other municipalities in the region, Uarini is characterised by its large territorial extent relative to its small population, a pattern shaped by the surrounding rainforest environment and the dispersed settlement that accompanies it.