Why are Mongolian autonomous counties located in western Liaoning?

The Mongolian autonomous counties in western Liaoning are located there because that region borders the Inner Mongolia Autonomous Region. Historically, the Mongol population has been concentrated toward this western frontier, reflecting the traditional distribution of non-Han peoples in the region.12

While the central plains of Liaoning have long been areas of Han Chinese peasant farming, the peripheries—including the west—were historically characterized by economies based on herding and estate farming, which were traditionally managed by people of Mongol or Manchu ancestry rather than Chinese settlers. Today, there are two autonomous counties representing the Mongolian minority: one centered on the coal town of Fuxin and another in the southwest at Kazuo.31