Arnoia
The River Arnoia, tributary of the Miño, as it passes through Allariz
Course of the Arnoia
Location
Country	Spain
Physical characteristics
Source	Sierra de San Mamede
• location	Vilar de Barrio, Galicia, Spain
Mouth
• location	Río Miño
• coordinates	42°15′15.8″N 8°09′8.7″W / 42.254389°N 8.152417°W / 42.254389; -8.152417
Length	84.5 km (52.5 mi)
Basin features
Progression	Minho→ Atlantic Ocean

The River Arnoia (Spanish: río Arnoia) is a tributary of the río Miño in Galicia, northwest Spain. At 84.5 kilometers, it is the longest river in the province of Ourense. The Spanish wine denominación de origen protegida of Ribeiro DOP is located at the confluences of the valleys formed by the rivers Miño, Avia, and Arnoia.^[1]

Etymology

The name territorio Arnogie (Arnogie territory) was first documented in 889 and fluvio Arnogie (Arnogie River) in 936. According to E. Bascuas, the toponym "Arnoia" would be derived from the Paleo-European base * Ar-n-, derived from the Indo-European root * er- 'flow, move', with hydronymic significance.^[2]