The river Someş (Hungarian Szamos) flows through Romania and Hungary.

It rises from two headstreams, the Someşul Mare, in the Rodna Mountains in Bistriţa-Năsăud County and the Someşul Mic in the Apuseni Mountains of Cluj County. The latter is in turn formed by the confluence of another two headstreams: the Someşul Cald and Someşul Rece.

The Someşul Mare and the Someşul Mic meet at Dej, from where the Someş flows westward, through Jibou and Satu Mare, to join the Tisza in Hungary, near Vásárosnamény.

The river Someş was known in antiquity by the name Samus.

The following rivers are the major tributaries to the river Someş: Lăpuş, Sălaj, Someşul Mic and Someşul Mare.