SHILKA RIVER

also spelled ilka river, Chita oblast (province), southeastern Russia, formed by the union of the Onon and Ingoda rivers. It flows 348 miles (560 km) northeast to unite with the Argun to form the Amur River on the RussiaChina border. The area of its drainage basin is 80,000 square miles (206,000 square km). The river is navigable for its entire length.