The Treaty of Tarbagatai (or Chuguchak; Chinese: 中俄勘分西北界約記) of 7 October [25 September O.S.] 1864 was a border protocol between Qing China and the Russian Empire that defined most of the western extent of their border in central Asia, between Outer Mongolia and the Khanate of Kokand. The signatories were, for Russia, Ivan Zakharov, consul-general of Ili, and Ivan Fedorovich Babkov, colonel of the Separate Siberian Corps of the General Staff, and, for China, Ming I, general of Uliastai; Hsi Lin, amban of Tarbagatai; and Bolgosu, Tarbagatai brigade commander. By this agreement, Russia gained about 350,000 square miles of territory at the expense of Chinese Xinjiang, and Lake Balkhash went from lying on the border to being entirely surrounded by Russia. It is sometimes numbered among the "une