The "Mouth of the Amazon" refers to the point where the Amazon River meets the Atlantic Ocean in northern Brazil. This area is characterized by a vast estuary, where freshwater from the river mixes with saltwater from the ocean. It is one of the largest river mouths in the world, spanning approximately 240 kilometers (150 miles) wide. The region is rich in biodiversity and supports various ecosystems, including mangroves and wetlands. It serves as a crucial habitat for numerous species, including fish, birds, and other wildlife. The mouth of the Amazon is also vital for local communities, providing resources and transportation routes.