| Ier River | |
| (Eriu River) | |
| River | |
| Countries | Romania,, Hungary |
|---|---|
| Counties | Satu Mare County, Bihor County |
| Tributaries | |
| - left | Ghirolt, Cubic, Checheţ, Santău, Zimoiaş, Sărvăzel, Raţ |
| - right | Sânmiclăuş, Vezendiu, Ieru Rece, Salcia, Moca |
| Villages | Mihăieni, Eriu-Sâncrai, Ghirolt, Răduleşti, Hotoan, Sudurău, Dindeşti, Andrid, Sălacea, Cherechiu, Săcuieni, Diosig |
| Mouth | Barcău |
The Ier River or Eriu River (Hungarian: Ér) is a tributary of the Barcău River in Romania. The Andrid Dam is constructed on this river.
The Hungarian name of the river means "brook". The Romanian name derives from that.