Onega, Russia town is also served by the Arkhangelsk–Murmansk rail line, which branches off in Obozerskaya railway station from the railroad between Moscow and Arkhangelsk and runs west to Onega and Belomorsk where it joins the railroad between Petrozavodsk and Murmansk. The railroad was built during World War II to secure the transport of goods from the harbor of Murmansk to central Russia. Onega is connected to Severodvinsk by a road. There are no all-seasonal roads on the left bank of the Onega River. The Onega is navigable downstream from the "selo" of Porog; there is regular passenger navigation. There is also
Lake Onega months. The highest water level is in June–August and the lowest is in March–April. Rivers bring of water per year to the lake, that is up to 74% of the water balance; the rest is provided by precipitation. Most of the lake water (84% or per year) outflows via a single River Svir, and the remaining 16% evaporates from the lake surface. There are frequent storms more characteristic of a sea than a lake; waves of are not uncommon and may even reach . The lake freezes near the coast and bays in late November and December and around mid-January