During the course of the 17th and 18th centuries , most regions inhabited by ethnic Mongols , notably Outer and Inner Mongolia became part of the Qing Empire . Even before the dynasty began to take control of China proper in 1644 , the escapades of Ligden Khan had driven a number of Mongol tribes to ally with the Manchu state . The Manchus conquered a Mongol tribe in the process of war against the Ming . Nurhaci 's early relations with the Mongols tribes was mainly an alliance . After Ligden 's defeat and death his son had to submit to the Manchus , and when the Qing dynasty was founded , most of what is now called Inner Mongolia already belonged to the new state . The Khalkha Mongols in Outer Mongolia joined in 1691 when their defeat by the Dzungars left them without a chance to remain independent . The Khoshud in Qinghai were conquered in 1723/24 . The Dzungars were finally destroyed , and their territory conquered , in 1756/57 during the Dzungar genocide . The last Mongols to join the empire were the returning Torgud Kalmyks at the Ili in 1771
Dzungar genocide
Dzungar genocide
Mongolia under Qing rule