Arkhangelsk Oblast the south-west of the Oblast drains into the Kema River which belongs to the basin of the Caspian Sea. The area in the Onega River basin containing the biggest lakes in the oblast, such as Lake Lacha, Lake Kenozero, Lake Undozero, and Lake Kozhozero. The tundra of the Nenets Autonomous Okrug also contains a number of bigger lakes. The river basin of the Pinega is characteristic of the karst, with a number of caves in the region. The White Sea coast within the Oblast is split into the Onega Bay (where the Onega is the major tributary), the Dvina Bay
Arkhangelsk serves as the administrative center of Primorsky District, even though it is not a part of it. As an administrative division, it is, together with five rural localities, incorporated separately as the city of oblast significance of Arkhangelsk—an administrative unit with the status equal to that of the districts. As a municipal division, the city of oblast significance of Arkhangelsk is incorporated as Arkhangelsk Urban Okrug. The mayor (as of July 2017) is Igor Viktorovich Godzish, who was elected in 2015. For administrative purposes, the city is divided into nine territorial okrugs: Nordavia (formerly Aeroflot Nord) airline has its head