Barra do Piraí is a municipality located in the state of Rio de Janeiro, Brazil. Situated at latitude 22º28'12" South and longitude 43º49'32" East, it lies approximately 114 km from the city of Rio de Janeiro.
The municipality covers a total area of 578.471 km² (223.349 sq mi). As of the 2020 census, the population of Barra do Piraí was recorded at 100,764 residents.