The Trebbia (stressed Trèbbia; Latin: Trebia) is a river predominantly of Liguria and Emilia Romagna in northern Italy.

It straddles eight comuni of the Province of Genoa: Torriglia, Rondanina, Propata, Fascia, Montebruno, Rovegno, Fontanigorda and Gorreto.

The Boreca is a mountain brook falling from the heights of the "four provinces" region generally too small to be shown on maps but visible in satellite photographs.

The river goes on under a good many small communities located up on the flanks of the hills before reaching the next good-sized town on it, Travo, and then Rivergaro.

The shrubbery includes the following species: Juniperus communis, Rubus fruticosus, Rubus idaeus, Polygala chamaebuxus, Daphne mezereum, Vaccinium myrtillus, Cornus mas, Euonymus europaea, Cytisus sessilifolius, Erica arborea, Ruscus aculeatus, Clematis vitalba, Lonicera caprifolium, Crataegus oxyacantha, Rosa canina, Spartium junceum.

[4] The Val Trebbia is within the endemic range of Moltoni's warbler, a subspecies of Sylvia cantillans better known in the western Mediterranean islands.

[6] The northern Apennines are a belt of northeast-southwest mountains on the coast of northwest Italy folded by transverse thrusting from sedimentary rock.

The streams draining it run primarily in a northeastern direction perpendicular to the line of the folds and project into the Po river an average of 50 km (31 mi) from the source.

[7] For much of their lengths, these heavily braided streams run through montane terrain that is minimally developed, is known for its wildlife, and remains in a pristine state.

The sediment eroded from the mountains is deposited in alluvial fans and terraces in the Po valley, which is heavily populated and in ancient times flooded regularly.

[8] Val Trebbia is covered with a blanket of rich soil reddish or brown in color from hematite an average of 4 m (13 ft) deep.

[9] Judging from the archaeological evidence, the Trebbia valley has been continuously occupied since the end of the Acheulian in the Paleolithic, about 150000 years ago.