Choibalsan (Mongolian: ) is the fourth-largest city in Mongolia. The name of the city was Bayan Tu'men until 1941, when it was renamed after the communist leader Khorloogiin Choibalsan. It is the capital of the province of Dornod. The city administrative unit's official name is Kherlen sum, with area of 281 km². It is situated at the Kherlen River, at an elevation of 747 m above sea level.