The Rio do Alegre is a waterway in the municipality of Santo Amaro, Maranhão, Brazil. It is situated within the broader region of the Lençóis Maranhenses, a significant national park area. A specific paddling route is documented as a GPS track available for download, indicating it is a navigable route for kayaking and canoeing. The river is associated with Praia Beira Rio, suggesting a beach or riverbank area that serves as a notable point along its course. For paddlers, kayak rentals are available in the area, typically priced around R$ 25.00, though the rental service itself is a separate transaction. Organized boat tours are also an activity on the river, with tours priced around R$ 15.00, not including travel to the starting point. The documented paddling trail is a point-to-point route, and the associated hiking trail near Praia Beira Rio covers 3.9 kilometers with an elevation gain of 70 meters, which may indicate the character of the surrounding terrain. The area's weather patterns are a consideration for trip planning, though specific seasonal water temperature averages or detailed water quality information are not provided. The river's setting within the Lençóis Maranhenses region implies a landscape of notable natural beauty, likely featuring sandy banks and dune systems characteristic of the area. No specific regulations, hazards, or seasonal restrictions for paddling are detailed.