Golfão Maranhense is a large coastal bay complex located in the state of Maranhão, Brazil. It is a region of significant geographical importance, containing the island of Upaon-Açu, where the city of São Luís is situated, and encompassing the major bays of São Marcos and São José de Ribamar. The area is noted for having the largest continuous mangrove forest in the world, which lines its shores. For paddlers, the most critical characteristic of the Golfão Maranhense is its extreme tidal range, "macro marés" with an amplitude exceeding six meters. This immense tidal fluctuation dictates that all trip planning must revolve around the tide tables, as currents will be exceptionally strong and water levels will change dramatically over a short period. Paddlers must be prepared to navigate vast exposed mudflats at low tide and powerful tidal flows. The bays within the Golfão, particularly São Marcos Bay, are major industrial and shipping hubs, featuring significant port infrastructure and mining complexes. Consequently, paddlers should expect substantial commercial vessel traffic and must exercise extreme caution, especially when crossing shipping channels. The water quality in parts of the bay, particularly near industrial areas like the Alumar mining complex, has been noted as a concern due to pollution. The region holds deep historical and cultural significance, evidenced by archaeological sites such as the Formoso stilt village, indicating a long history of human habitation adapted to this dynamic aquatic environment. Wildlife of interest includes the West Indian manatee, which inhabits the mangrove areas. There are no specific paddling restrictions mentioned, but the combination of massive tides, heavy ship traffic, and industrial activity demands a high level of skill, preparedness, and local knowledge for anyone venturing onto these waters.