The largest lake in Europe, located in northwestern Russia about 25 miles (40 km) east of St. Petersburg. It is 6,700 square miles (17,600 square km) in area—exclusive of islands—and 136 miles (219 km) long, with an average width of 51 miles (82 km) and an average depth of 167 feet (51 m). Its greatest depth, at a point west of Valaam Island, is 754 feet (230 m). Lake Ladoga's basin has a total area of about 100,000 square miles (259,000 square km).