| Barcău | |
| Name Other: | Berettyó |
| Map: | Raul Barcau.png |
| Subdivision Type1: | Countries |
| Subdivision Name1: | Romania and Hungary |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Romania: Hungary: |
| Subdivision Type3: | Towns |
| Length: | 167km (104miles) |
| Source1: | Plopiș Mountains |
| Source1 Location: | near Boghiș, Sălaj County, Romania |
| Mouth: | Crișul Repede |
| Mouth Location: | near Szeghalom, Békés County, Hungary |
| Mouth Coordinates: | 46.9833°N 21.1236°W |
| Basin Size: | 5812km2 |
| Tributaries Right: | Ier |
The Barcău or Bereteu (Romanian or Berettyó in Hungarian) is a river which has its origin in Sălaj County, Romania. It is about 167km (104miles) long with a watershed area of 5812km2.[1] After crossing Bihor County in Romania and Hajdú-Bihar and Békés County in Hungary, it flows into the Sebes-Körös (Romanian: Crișul Repede) near Szeghalom. Its length in Romania is 134km (83miles).
The upper reach of the Barcău, upstream of the junction with the Răchita is locally called the Ștei, Berchesei or Bărcașu. The reach between the junctions with the Răchita and the Toplița is locally known as the Tusa. The name Barcău is only used following its confluence with the Toplița.[2] [3]
The following towns and villages are situated along the river Barcău, from source to mouth: in Romania: Valcău de Jos, Boghiș, Nușfalău, Ip, Suplacu de Barcău, Balc, Abram, Marghita, Abrămuț, Chișlaz, Sălard, Tămășeu, in Hungary Kismarja, Pocsaj, Gáborján, Berettyóújfalu, Szeghalom.
The following rivers are tributaries to the river Barcău (from source to mouth):