Leningrad Oblast of two great lakes of the European Part of Russia, Lake Ladoga and Lake Onega. Its northeastern part, between the Gulf of Finland and Lake Ladoga, occupies the Karelian Isthmus. Some islands in the Gulf of Finland (including Kotlin, on which the city of Kronstadt has been built) and Lake Ladoga (including Konevets) also belong to the oblast. Much of the area of the oblast belongs to the drainage basin of the Neva, which is the only outflow of Lake Ladoga. Whereas the Neva, which flows to the Gulf of Finland (the city of Saint Petersburg is located in its
Finnish Ladoga Naval Detachment Finns had intended to mount further landing operations to secure the island of Valamo but Soviets withdrew from there as well as from most of the other island on the lake voluntarily. Finnish forces took control of the island of Valamo on 20 September and island of Konevitsa on 25 September. Since Soviet forces remained inactive on lake Ladoga for the rest of the 1941 Finnish naval forces concentrated on security and transport duties. After Finns had captured maps of the Soviet naval minefields on the lake several boats were detailed for minesweeping duties which however yielded no results nor