Lake Peipus Lake Peipus Lake Peipus (; ; ) is the largest transboundary lake in Europe, lies on the border between Estonia and Russia. The lake is the fifth-largest in Europe after Lake Ladoga and Lake Onega (in Russia north of St. Petersburg), Lake Vänern (in Sweden), and Lake Saimaa (in Finland). Lake Peipus represents a remnant of a body of water which existed in this area during an Ice Age. It covers , and has an average depth of , the deepest point being . The lake has several islands and consists of 3 parts: The lake is used for fishing
Lake Ladoga due to uplift of the Baltic Shield in the north. It has been hypothesized, but not proven, that waters of the Litorina Sea, the next brackish-water stage of the Baltic, occasionally invaded Ladoga between 7,000 and 5,000 BP. Around 5,000 BP the waters of the Saimaa Lake penetrated Salpausselkä and formed a new outlet, River Vuoksi, entering Lake Ladoga in the northwestern corner and raising its level by 1–2 m. The River Neva originated when the Ladoga waters at last broke through the threshold at Porogi into the lower portions of Izhora River, then a tributary of the Gulf of