Tresviso is a municipality in the autonomous community of Cantabria, Spain. It lies at an elevation of about 907 metres (2,976 ft) above sea level within the Picos de Europa of the Cantabrian Mountains.
The village sits on a mountain ledge roughly 800 metres (2,600 ft) above the bottom of the Deva River valley. Although it belongs to Cantabria, its only road access is a narrow route over a 1,320-metre (4,330 ft) high pass from Sotres in the neighbouring province of Asturias. On the Cantabrian side, the alternative approach is a strenuous three-hour hike from the N621 highway along the Deva, a route featuring many switchbacks.