In form, if not in fact, the structure of Chinese sub-provincial units goes as follows:

• Region (province)
  • Prefecture
    • County (and/or district)

There may be one or many counties/districts in a prefecture and one or many prefectures in a region.  China also has the idea, if not in fact, of autonomous regions, prefectures, and counties.  The general naming structure is: <placename> <ethnicity> <“autonomous”> <unit>, where unit could be region, prefecture, or county/district.  So, for example, you have, officially, the “Xinjiang Uyghur Autonomous Region.”  But the autonomous designation is, as it were, autonomous, so you end up with situations like:

• Xinjiang Uyghur Autonomous Region
  • Bayin’gholin Mongol Autonomous Prefecture
    • Yanqui Hui Autonomous County

So that’s a nominally autonomous region of Hui (Han Chinese Muslims) within a Mongol autonomous prefecture within a Uyghur autonomous region, none of which are, of course, in the slightest bit autonomous.