Minho (Span mēnˈyō, Port. mēnˈyō) [key], Span. Miño, river, c.210 mi (340 km) long, rising in Galicia, NW Spain, and flowing generally SW to the Atlantic Ocean. The Sil is its chief tributary. The lower part of the Minho forms a section of the border between Spain and Portugal. Hydroelectricity is produced near Ourense, Spain.