Template: Infobox River / Obsolete
It is the largest tributary of the Saimaa lake system. The river connects the two largest lakes in the countryside of North Karelia, Pielinen and Pyhäselkä. At its confluence with the Pyhäselkä is the town of Joensuu.
The Pielisjoki arose after the last Ice Age, when the Uimaharju -Os broke under the pressure of the water of Pielinen. Cause was a postglacial land uplift, which led to the outflow direction of the Pielinen, which was previously drained to the north changed.
Ten navigation locks were built in the late 19th century along the river. In the 1950s and 1960s, two hydroelectric power plants came on Pielisjoki: Kaltimo ( 24 MW, 10 m drop height ) and Kuurna ( 18 MW, 6.9 m drop height ). At the same time new channels were built, which replaced the old shipping. The lock at Kaltimo has 9 m to the greatest height difference in Finland.
The Pielisjoki leaves the Pielinen at its southern end. Then it flows through the two lakes Rukavesi and Rahkeenvesi. In the latter Koitajoki coming from the left strikes the Pielisjoki. 2 km effluent flows, most of that coming from Koitajoki water in the Pielisjoki. This was previously diverted to the southeast, Pamilo hydropower plant. A few kilometers further happening of the site Pielisjoki Eno and sets his course continued to Joensuu.