Location: Dornod province, the most eastern part of Mongolia .
Features: Khalkh Gol is the biggest river in Dornod province. This river runs through Khalkh Gol soum about 240 km and flows into Buir Lake, bordering the line between Mongolia and China. From May to September 1939, the river was the battle field between Soviet and Mongolian forces against Japanese Kwantung Army.