The Guadu Grande is 9.49 kilometres (5.90 mi) long and flows through the communes of Brando, Ogliastro and Olcani.

[1] It rises to the north of the 1,307 metres (4,288 ft) Monte Stello in the west of the commune of Brando.

It flows in a generally northwest direction past the villages of Olcani and Ogliastro, then turns to the southwest and enters the sea at the north end of the beach of the Marine d'Albo.

The last section of its course flows through a wetland, The Torra d'Albu stands at the south end of the beach.

[2] The lower part of the river valley and the Marine d'Albo have been designated a Zone naturelle d'intérêt écologique, faunistique et floristique (ZNIEFF) covering 15 hectares (37 acres).