The Rio Pericumã is a river located in the state of Maranhão in northeastern Brazil. It flows through the Baixada Maranhense region, an area known for its extensive wetlands and seasonal flooding. The river's coordinates are approximately 2°17′S 44°42′W. The overall character of the river is defined by its rich aquatic ecosystem. It supports a great variety of flora and fauna, including numerous species of aquatic plants, also known as macrophytes. This dense and diverse plant life contributes significantly to the river's aesthetic, creating a lush, green environment that is characteristic of the region's flooded fields. The presence of this extensive aquatic vegetation is a key natural feature for paddlers to observe, though it may also influence navigation in certain areas. The river is part of a broader ecological landscape that is significant to the local environment.