From there it flows north until it reaches the Atlantic Ocean near Arecibo.

[1] The tributaries lie along the side of the Cerro de Punta and the Utuado pluton.

[2] The tributaries to Río Grande de Arecibo basin are Vacas, Pellejas, Garzas, Saltillo, Cidra, Grande de Jayuya, Caguana, Caonillas, Yunés, Limón, Jauca, Tanamá and Santiago rivers.

[3] In mid 2018, the United States Army Corps of Engineers announced it would be undertaking a major flood control project of the river, with a budget of $82.9 million.

[4] In mid 2021, funding was appropriated for work on the Río Grande de Arecibo, including work to improve the natural habitat of local species, including the Puerto Rican crested toad and a Río Grande de Arecibo canalization project was set to begin in 2023.