The Irtysh River flows from the Kolyvan Mountains to the Middle Sea. It is navigable for the vast majority of its length and is blessed with wind patterns opposite with the current, making it an efficient trading route for southern Matriarchate of Periaslavl.
Much of it runs through Irtysh Oblast.
There are many cities on its banks, including Alexandrovsk, Chelyabinsk, Ryazan, Tarnovo, and Vladikavkaz.