The Someș (Romanian pronunciation: [ˈsomeʃ]) or Szamos (German: Somesch or Samosch) is a left tributary of the Tisza in Hungary and Romania. It has a length of 415 km (258 mi) (including its source river Someșul Mare), of which 50 km are in Hungary. The Someș is the fifth largest river by length and volume in Romania. The hydrographic basin forms by the confluence at Mica, a commune about 4 km upstream of Dej, of Someșul Mare and Someșul Mic rivers. Someșul Mic (formed by the confluence of Someșul Rece with Someșul Cald) originates in the Apuseni Mountains, and Someșul Mare springs from the Rodna Mountains.
Someșul Mare has a length of 130 km and an area of 5,033 km and a slight asymmetry in favor of the left side of the basin. For the entire basin of Someș, the asymmetry on left becomes pronounced between Dej and Ardusat to change in the opposite direction after receiving the Lăpuș on the right side. The valley of Someșul Mare has much auriferous alluvium that, until the early 20th century, were brought to the surface using traditional tools. Specialists say that in the Someșul Mare were found grains of gold of 21 carats.