| Trotuș | |
| Name Other: | Tatros |
| Map: | Trotuș.png |
| Map Size: | 280px |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Harghita, Bacău, Vrancea |
| Subdivision Type3: | Towns |
| Subdivision Name3: | Comănești, Onești, Adjud |
| Length: | 162km (101miles) |
| Source1: | Ciuc Mountains |
| Mouth: | Siret |
| Mouth Location: | Adjud |
| Mouth Coordinates: | 46.0111°N 27.2092°W |
| Basin Size: | 4456km2 |
| Tributaries Left: | Asău, Tazlău |
| Tributaries Right: | Uz |
The Trotuș (Hungarian: Tatros) is a river in eastern Romania, a right tributary of the river Siret.[1] It emerges from the Ciuc Mountains in the Eastern Carpathians and joins the Siret in Domnești-Sat near Adjud after passing through Comănești and Onești in Bacău County.[2] The total length of the Trotuș from its source to its confluence with the Siret is 162km (101miles).[3] Its basin area is 4456km2.[3] [4]
The following towns and villages are situated along the river Trotuș, from source to mouth: Lunca de Sus, Lunca de Jos, Ghimeș-Făget, Palanca, Agăș, Comănești, Dărmănești, Târgu Ocna, Onești and Adjud.
The following rivers are tributaries to the Trotuș (from source to mouth):
Left: Gârbea, Valea Întunecoasă, Antaloc, Valea Rece, Bolovăniș, Tărhăuș, Șanț, Cuchiniș, Brusturoasa, Caminca, Șugura, Dracău, Agăș, Seaca, Ciungi, Asău, Urmeniș, Plopul, Larga, Cucuieți, Vâlcele, Gălian, Caraclău, Tazlău and Pârâul Mare
Right: Comiat, Bothavaș, Ugra, Boroș, Valea Capelei, Aldămaș, Popoiul, Ciugheș, Cotumba, Grohotiș, Sulța, Ciobănuș, Șopan, Uz, Dofteana, Slănic, Nicorești, Oituz, Cașin, Găureana, Gutinaș, Bogdana, Gârbovana, Căiuți, Popeni, Bâlca and Domoșița