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 Governorate Arkhangelsk Oblast (and later the Arkhangelsk Viceroyalty) was subdivided into seven uyezds (the administrative centers, which all had the town status, are given in parentheses), Mezen, Onega, and Pinega were incorporated as towns in 1780 just to become the uyezd towns. Kola was incorporated in 1784. In 1801, portions of the Povenetsky Uyezd were transferred to the Olonets Governorate, while the Kemsky Uyezd, with its center in Kem, was left to remain in the Arkhangelsk Governorate. In 1854, the town of Kola was destroyed during the Crimean War, and Kolsky Uyezd was merged into the Kemsky Uyezd. In 1883, the