| Miera River | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Spain |
| Subdivision Type2: | Autonomous community |
| Subdivision Name2: | Cantabria |
| Subdivision Type3: | Region |
| Length: | 57km (35miles) |
| Discharge1 Location: | mouth |
| Source1 Location: | Castro Valnera |
| Mouth: | Cantabrian Sea |
| Mouth Elevation: | 0m (00feet) |
| Basin Size: | 295km2 |
The Miera River (Spanish; Castilian: Río Miera) is a river on the Cantabrian slope of the Iberian Peninsula that runs entirely within the autonomous community of Cantabria (Spain). It originates in the area known as Los Villares, in Castro Valnera at 1280 m and flows into the Cantabrian Sea through the Cubas estuary.
On its way, it crosses the Miera Valley, a narrow valley to which it gives its name, until it reaches the locality of Solares. At this point, the valley blurs and the river continues its course, marking the dividing line between the municipalities of Marina de Cudeyo and Ribamontán al Monte until it reaches the sea, where it delivers its waters to Santander Bay through the Cubas estuary.[1]
The name Miera probably derives from Magrada or Mégrada cited by Pomponius Mela in the 1st century.[2]