Lake Lacha Lake Lacha Lake Lacha () is a freshwater lake, located in the south of Kargopolsky District of Arkhangelsk Oblast in Russia, south of the town of Kargopol. It is the largest lake in Arkhangelsk Oblast, with a surface area of and a basin area of . Lake Lacha is the source of the Onega River, one of the major waterways of the White Sea basin. The etymological origin of the name is unclear. The river basin of Lake Lacha includes the southern and western parts of Kargopolsky District of Arkhangelsk Oblast, as well as north-west of Vologda Oblast. In particular,
Lake Onega a total area of about . Whereas the most famous is Kizhi, which contains historical wooden churches of the 18th century, the largest island is Big Klimenetsky with an area of . It contains a few settlements, a school and an hill. Other large islands are Big Lelikovsky and Suysari. The lake banks are low and are flooded with raising water level. They are therefore swampy and are rich in reed, hosting ducks, geese and swans. The coastal region is covered with dense virgin forests. Major tree types are coniferous, but also common are lime (linden), elm and European alder.