The Pará River, also called Parauaú River, Jacaré Grande River, Marajó River Channel, Macacos River Channel, Santa Maria River Channel and Bocas Bay, is a watercourse and immense estuarine complex that functions as a canal between the rivers Amazon, Tocantins, Campina Grande and Marajó Bay, in addition to numerous other smaller rivers. It can also be considered a distributary channel of the Tocantins River.

The Amazon River in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile.