| Arnoia | |
| Map: | Arnoia.png |
| Map Size: | 280px |
| Subdivision Type1: | Country |
| Subdivision Name1: | Spain |
| Length: | 84.5km (52.5miles) |
| Source1: | Sierra de San Mamede |
| Source1 Location: | Vilar de Barrio, Galicia, Spain |
| Mouth Location: | Río Miño |
| Mouth Coordinates: | 42.2544°N -8.1524°W |
The River Arnoia (Spanish; Castilian: 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]
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]