The source of the Spanish Miño lies about 50 km. north of Lugo in Galicia. The river passes just south of the walls of this old Roman city and flows south through canyons until the valley widens north of Ourense. The river has been harnassed in reservoirs by Fenosa, Spain's electric company, from Portomarin to Frieira. In its length it has the following reservoirs: Belesar with 654 Hm3, Peares with 182 Hm3, Velle with 17 Hm3, Castrelo with 60 Hm3 and Frieira with 44 Hm3.
Twenty kilometers north of Ourense at Os Peares the Miño receives the waters of its main tributary, the Sil. Passing Ourense, the river flows in a southwest direction until reaching the Portuguese border near Melgaço. There is one major dam at Frieira near the town of Rivadavia. This region is famous for production of the Ribeira wine.
The Portuguese Minho divides the two countries for about 80 km. The valley is a lush, green agricultural area where every square metre of land is used to produce corn, potatoes, cabbage, or just grass, depending on the time of year, and everywhere edging the fields, rivers and gardens, wherever there is space, the vines which produce the light, slightly sparkling “Vinho Verde” peculiar to this area. The very best of these, Alvarinho, is produced in the area around Monção and Melgaço.
Passing the medieval towns of Melgaço and Monção the Minho divides the Spanish Tui and Portuguese Valença do Minho, towns that guarded an important crossing for road and rail. Both towns preserve fortifications and are national monuments. The Minho reaches the Atlantic near Caminha.
Despite being un-navegable except for very shallow craft, the Minho has been very important in the history of Galicia and northern Portugal, lending its name to one of the most important historical regions of that country.