a river in the Taimyr (Dolgan-Nenets) Autonomous Okrug, Krasnoiarsk Krai, RSFSR.
The Piasina is 818 km long and drains an area of 182,000 sq km. It originates in Lake Piasino and empties into Piasina Inlet of the Kara Sea. From Lake Piasino, the river cuts through morainal ridges and flows through a narrow valley to the mouth of the Dudypta (144 km). Further downstream it meanders through the Northern Siberian Lowland and then branches near the mouths of the Iangoda and Mokoritto rivers. Below its confluence with the Pura the Piasina cuts through the Byrranga Mountains in a narrow valley and then flows in a slightly demarcated valley along the maritime lowland. The Piasina forms a branched estuary and a sandbar where it flows into the sea.
The basin of the Piasina River contains more than 60,000 lakes with a total area of 10,450 sq km. The river is fed mainly by snow (60 percent). It is at high water from June through October. Its mean flow rate at the source is 560 cu m per sec, and at its mouth, 2,600 cu m per sec. At low water, the effect of sea tides is felt as far as the mouth of the Tareia (309 km). The Piasina freezes in late September or early October, and the ice breaks up in June. The river is navigable. The Piasina and its tributaries are rich in fish.