The Bolshoy Irgiz (Russian: Большой Ирги́з, literally Great Irgiz) or Irgiz is a river in Samara and Saratov Oblast, Russia, a left tributary of the Volga, south of the Samara River. It is 675 km long and the area of its drainage basin is 24,000 km2. Its headwaters are at the Obshchy Syrt adjoining the Ural River basin. It flows west and joins the Volga south of Samara. Irgiz\’s meandering riverbed passes the steppes. The river has snow feeding. The town of Pugachyov is located along the Irgiz. The river flows to the Volgograd Reservoir of the Volga downstream Balakovo, near Volsk.
