The Elvo (Piedmontese: Elv) is a 53-kilometre (33 mi) torrent (an intermittent stream) in the Piedmont region of north-west Italy and is the principal tributary of the Cervo.

The river’s source is at an elevation of about 2,600 metres (8,500 ft) on the slopes of Monte Mars, in the heart of the Biellese Prealps.

From here its broad pebbly shores follow the edge of the Bessa nature reserve, which lies to its right and is part of the Riserva naturale orientata delle Baragge.

Near Salussola it enters into the plains of Vercelli and follows a slower and more sinuous course before emptying into the Cervo near Quinto Vercellese.

The Elvo has a regime typical of a prealpine Italian torrent with maximum discharges in the autumn and spring together with a tendency to dry up in the summer and winter months.