A river basin is the area of land where all the water that drains into a specific river and its tributaries flows. This includes rainwater, melting snow, and groundwater. River basins are important for managing water resources, as they help to collect and distribute water across the landscape. The boundaries of a river basin are defined by watersheds, which are elevated areas like hills or mountains that separate one basin from another. Each river basin can vary in size and shape, influencing the ecosystems and communities that depend on the water it provides.