RÃÂo Inabón is one of the 14 rivers in the municipality of Ponce, Puerto Rico. With a length of some , it is Ponce's second longest river after RÃÂo Jacaguas. It is fed by the RÃÂo Anón, RÃÂo Guayo (which itself is fed by the Chiquita Brook and the Indalecia Brook) and the Emajagua Brook. It is also fed by RÃÂo Bacas and RÃÂo de las Raices. Originating at an altitude of approximately , it forms at a higher altitude than any of the other 13 rivers in the municipality, and at one of the highest points of any river in Puerto Rico. With a watershed area covering 38.18 square miles, RÃÂo Inabón also has the second largest basin area of any of the municipality's 14 rivers after RÃÂo Jacaguas.
RÃÂo Inabón has its origin at above sea level in Cerro Camacho, in barrio Anón, near Anón's boundary with the municipality of Jayuya. The river runs mostly parallel to PR-511.
"A provision in The Treaty of Paris of 1898 grants the Serrallés family exclusive rights to the RÃÂo Inabón. This river winds through Puerto RicoâÂÂs volcanic mountains, and is the exclusive water source for DonQ Rum". Today RÃÂo Inabón is one of the most popular rivers for swimming in southern Puerto Rico. Some 10 private reservoirs in the Ponce area are fed by the waters of RÃÂo Inabón.
In January 2011, Puerto Rico Representative VÃÂctor Vassallo Anadón presented a bill into the Puerto Rico House of Representatives that would improve the sewer system of residents near the river to avoid contaminating it with sewer waters.
The fern Thelypteris inabonensis found at the headwaters of RÃÂo Inabón and at the Toro Negro State Forest has been identified by the U.S. Fish and Wildlife Service as an endangered species.
The flow of water in the river is controlled by the floodgates at Toa Vaca Lake, located in the municipality of Villalba. RÃÂo Inabon has a discharge of 15,000 ft<sup>3</sup>/s. The Inabón has been known to overflow easily in times of heavy rains. Several rescues have taken place when the river has increased its level rapidly, a phenomenon known as flash flood. Due to its proximity to the eastern end of Aeropuerto Mercedita, the river has affected the operation of the airport in times of heavy rains. This was the case with the hurricane Maria in September 2017.
The following table summarizes the course of RÃÂo Inabón in terms of roads crossed. Roads are listed as the river flows from its origin in the mountains of Barrio Anón, north of the city of Ponce, to the Caribbean Sea in the south (N/A = Data not available):