Ergune or Argun (Mongolian: Эргүнэ мөрөн, Ergüne mörön; Manchu: Ergune bira; Chinese: 额尔古纳河; pinyin: É'ěrgǔnà Hé; Russian: Аргу́нь) is the river which is a part of the Russia–China border. Its upper reaches are known as Hailar River (Chinese: 海拉尔河; pinyin: Hăilā'ěr Hé) in China. Its length is 1,621 kilometres (1,007 mi). The Ergune marks the border (established by the Treaty of Nerchinsk in 1689) between Russia and China for about 944 kilometres (587 mi), until it meets the Amur River.