Ier

The Ier or Eriu () is a right tributary of the river Barcău ("Berettyó") in Romania and Hungary. It discharges into the Barcău in Pocsaj. The Andrid Dam is constructed on this river. The Ier flows through the villages Mihăieni, Eriu-Sâncrai, Ghirolt, Rădulești, Hotoan, Sudurău, Dindești, Andrid, Sălacea, Cherechiu, Săcueni, Diosig in Romania, and Pocsaj in Hungary. In Romania, its length is and its basin size is .
Hydronymy.
The Hungarian name of the river means "brook". The Romanian name derives from that.
Tributaries.
The following rivers are tributaries to the river Ier: