Where does most river water enter the Arctic Ocean?

Most river water enters the Arctic Ocean through the marginal shallow seas located along the Eurasian sector, which includes the Chukchi, East Siberian, Laptev, Kara, and Barents seas.2

Major rivers that flow northward into the Arctic Ocean include the Ob, Irtysh, Yenisey, Lena, Yana, Indigirka, and Kolyma rivers. In North America, the Mackenzie River and the Colville River are the primary contributors to the ocean's freshwater input. While these marginal seas occupy 36 percent of the Arctic Ocean's area, they receive the vast majority of river discharge, which significantly influences the ocean's surface-water conditions.12