Dvina Bay streams. There are many small islands in the Dvina Bay as well, the biggest being Mudyug Island. A national park, Onezhskoye Pomorye National Park, was open on the Onega Peninsula on 26 February 2013. The Dvina Bay is limited by the Onega Peninsula from the west. At the eastern side, the shore steeply rises to a plateau (White Sea - Kuloy Plateau) which drains east into the Soyana, a major tributary of the Kuloy. The Onega Bay shore is often referred to as "Letny Bereg" (Summer Coast), and the eastern shore of the bay is "Zimny Bereg" (Winter Coast). The
Primorsky District, Arkhangelsk Oblast first-level administrative division of Russia kept changing. In 1930, the okrug was abolished, and the district was subordinated to the central administration of Northern Krai. In 1936, the krai was transformed into Northern Oblast. In 1937, Northern Oblast itself was split into Arkhangelsk Oblast and Vologda Oblast. Primorsky District remained in Arkhangelsk Oblast ever since. The location of the administrative center of the district was moved several times until Arkhangelsk finally became the center. On December 17, 1940, Belomorsky District was established on the Onega Peninsula, in the areas which previously were parts of Primorsky and Onezhsky Districts. The administrative